Make common/30-disable-gettys and {edgy,intrepid}/30-disable-gettys more similar

hooks/common/30-disable-gettys

@@ -4,9 +4,6 @@
 # first console - that must remain so that 'xm console ...' works
 # correctly.
 #
-# Steve
-# --
-# http://www.steve.org.uk/
 
 
 prefix=$1

hooks/edgy/30-disable-gettys

@@ -39,7 +39,7 @@ rm -f ${prefix}/etc/event.d/tty[!1]
 #
 if [ ! -z "${serial_device}" ]; then
 
-    serial_device=`basename ${serial_device}`
+    serial_device=`basename $serial_device`
 
     # Let the user know.
     logMessage "Replacing default serial device (hvc0) with ${serial_device}"

hooks/intrepid/30-disable-gettys

@@ -39,7 +39,7 @@ rm -f ${prefix}/etc/event.d/tty[!1]
 #
 if [ ! -z "${serial_device}" ]; then
 
-    serial_device=`basename ${serial_device}`
+    serial_device=`basename $serial_device`
 
     # Let the user know.
     logMessage "Replacing default serial device (hvc0) with ${serial_device}"