Use apt-config dump to determine Dom0's APT proxy settings.

This is the official way, needs no own parsing (therefore less
fault-prone) and shorter. Also fixes Debian bug #560011 -- the manual
parsing did not catch all syntax variants.

Also add some comments before /etc/apt/sources.list generation in the
Ubuntu hooks.

hooks/dapper/20-setup-apt

@@ -30,28 +30,17 @@ logMessage Script $0 starting
 
 #
 # Attempt to auto-magically detect the use of a Proxy for apt-get, and
-# replicate that setup in our new guest.
+# replicate that setup in our new guest via apt-config dump and save
+# the setting to the proxy guess file.
 #
+logMessage The use of a proxy detected.
+apt-config dump | grep -i Acquire::HTTP::Proxy \
+    > ${prefix}/etc/apt/apt.conf.d/proxy-guess
+
+
 #
-#  Process any of the present apt-conf setup lines.
+# Setup the sources.list file for new installations of Ubuntu GNU/Linux.
 #
-for i in /etc/apt/apt.conf /etc/apt/apt.conf.d/* ; do 
-
-    #
-    # If the file exists.  (Need this in case the literal glob fails.)
-    #
-    if [ -e $i ] ; then
-
-        #
-        # Save the matching line(s) to the proxy guess file.
-        #
-        logMessage The use of a proxy detected.
-        grep -i HTTP::Proxy $i >> ${prefix}/etc/apt/apt.conf.d/proxy-guess
-    fi
-done
-
-
-
 cat <<E_O_APT > ${prefix}/etc/apt/sources.list
 #
 #  /etc/apt/sources.list

hooks/debian/20-setup-apt

@@ -29,26 +29,12 @@ logMessage Script $0 starting
 
 #
 # Attempt to auto-magically detect the use of a Proxy for apt-get, and
-# replicate that setup in our new guest.
+# replicate that setup in our new guest via apt-config dump and save
+# the setting to the proxy guess file.
 #
-#
+logMessage The use of a proxy detected.
-#  Process any of the present apt-conf setup lines.
+apt-config dump | grep -i Acquire::HTTP::Proxy \
-#
+    > ${prefix}/etc/apt/apt.conf.d/proxy-guess
-for i in /etc/apt/apt.conf /etc/apt/apt.conf.d/* ; do 
-
-    #
-    # If the file exists.  (Need this in case the literal glob fails.)
-    #
-    if [ -e $i ] ; then
-
-        #
-        # Save the matching line(s) to the proxy guess file.
-        #
-        logMessage The use of a proxy detected.
-        grep -i HTTP::Proxy $i >> ${prefix}/etc/apt/apt.conf.d/proxy-guess
-    fi
-done
-
 
 
 #

hooks/edgy/20-setup-apt

@@ -30,30 +30,17 @@ logMessage Script $0 starting
 
 #
 # Attempt to auto-magically detect the use of a Proxy for apt-get, and
-# replicate that setup in our new guest.
+# replicate that setup in our new guest via apt-config dump and save
+# the setting to the proxy guess file.
 #
+logMessage The use of a proxy detected.
+apt-config dump | grep -i Acquire::HTTP::Proxy \
+    > ${prefix}/etc/apt/apt.conf.d/proxy-guess
+
+
 #
-#  Process any of the present apt-conf setup lines.
+# Setup the sources.list file for new installations of Ubuntu GNU/Linux.
 #
-for i in /etc/apt/apt.conf $(run-parts --list /etc/apt/apt.conf.d) ; do
-
-
-    #
-    # If the file exists.  (Need this in case the literal glob fails.)
-    #
-    if [ -e $i ] ; then
-
-        #
-        # Save the matching line(s) to the proxy guess file.
-        #
-        logMessage The use of a proxy detected.
-
-        grep -v '^//' $i | grep -i HTTP::Proxy >>${prefix}/etc/apt/apt.conf.d/proxy-guess
-    fi
-done
-
-
-
 cat <<E_O_APT > ${prefix}/etc/apt/sources.list
 #
 #  /etc/apt/sources.list

hooks/intrepid/20-setup-apt

@@ -30,30 +30,17 @@ logMessage Script $0 starting
 
 #
 # Attempt to auto-magically detect the use of a Proxy for apt-get, and
-# replicate that setup in our new guest.
+# replicate that setup in our new guest via apt-config dump and save
+# the setting to the proxy guess file.
 #
+logMessage The use of a proxy detected.
+apt-config dump | grep -i Acquire::HTTP::Proxy \
+    > ${prefix}/etc/apt/apt.conf.d/proxy-guess
+
+
 #
-#  Process any of the present apt-conf setup lines.
+# Setup the sources.list file for new installations of Ubuntu GNU/Linux.
 #
-for i in /etc/apt/apt.conf $(run-parts --list /etc/apt/apt.conf.d) ; do
-
-
-    #
-    # If the file exists.  (Need this in case the literal glob fails.)
-    #
-    if [ -e $i ] ; then
-
-        #
-        # Save the matching line(s) to the proxy guess file.
-        #
-        logMessage The use of a proxy detected.
-
-        grep -v '^//' $i | grep -i HTTP::Proxy >>${prefix}/etc/apt/apt.conf.d/proxy-guess
-    fi
-done
-
-
-
 cat <<E_O_APT > ${prefix}/etc/apt/sources.list
 #
 #  /etc/apt/sources.list

hooks/karmic/20-setup-apt

@@ -30,30 +30,17 @@ logMessage Script $0 starting
 
 #
 # Attempt to auto-magically detect the use of a Proxy for apt-get, and
-# replicate that setup in our new guest.
+# replicate that setup in our new guest via apt-config dump and save
+# the setting to the proxy guess file.
 #
+logMessage The use of a proxy detected.
+apt-config dump | grep -i Acquire::HTTP::Proxy \
+    > ${prefix}/etc/apt/apt.conf.d/proxy-guess
+
+
 #
-#  Process any of the present apt-conf setup lines.
+# Setup the sources.list file for new installations of Ubuntu GNU/Linux.
 #
-for i in /etc/apt/apt.conf $(run-parts --list /etc/apt/apt.conf.d) ; do
-
-
-    #
-    # If the file exists.  (Need this in case the literal glob fails.)
-    #
-    if [ -e $i ] ; then
-
-        #
-        # Save the matching line(s) to the proxy guess file.
-        #
-        logMessage The use of a proxy detected.
-
-        grep -v '^//' $i | grep -i HTTP::Proxy >>${prefix}/etc/apt/apt.conf.d/proxy-guess
-    fi
-done
-
-
-
 cat <<E_O_APT > ${prefix}/etc/apt/sources.list
 #
 #  /etc/apt/sources.list