Handle potentially empty gateway setting properly

… in hooks/common/40-setup-networking-deb

Thanks Simone Caruso!

debian/changelog

@@ -16,6 +16,8 @@ xen-tools (4.4~dev-1) UNRELEASED; urgency=low
     xen-create-image, neither xt-create-xen-config nor xm support it.
   * Refactoring: Replace all occurrences of "! -z" by "-n" in hooks and
     bash completion.
+  * Handle potentially empty gateway setting properly in
+    hooks/common/40-setup-networking-deb. Thanks Simone Caruso!
 
  -- Axel Beckert <abe@debian.org>  Fri, 23 Aug 2013 21:13:07 +0200
 

hooks/common/40-setup-networking-deb

@@ -85,6 +85,14 @@ setupStaticNetworking ()
       bcast=" broadcast ${broadcast}"
     fi
 
+    #
+    # gateway address?
+    #
+    gateway='';
+    if [ -n "${gateway}" ]; then
+      gateway=" gateway ${gateway}"
+    fi
+
     #
     # We have a static IP address
     #
@@ -100,7 +108,7 @@ iface lo inet loopback
 auto eth0
 iface eth0 inet static
  address ${ip1}
- gateway ${gateway}
+${gateway}
  netmask ${netmask}
  ${bcast}
  ${point}