network: fix 'qubes-uplink-eth0' NetworkManager connection (#1280)

According to the specification[1], the setting name is 'addresses', not
'address'.  The later apparently worked on some NetworkManager versions,
but for example not on the one in Debian wheezy. Also fix value
format (IP;netmask;gateway).

[1] htts://developer.gnome.org/NetworkManager/unstable/ref-settings.html

Fixes QubesOS/qubes-issues#1280

network/setup-ip

@@ -57,9 +57,9 @@ __EOF__
             echo "dns=$gateway;$secondary_dns" >> $nm_config
         fi
         if [ "x$disablegw" != "x1" ]; then
-            echo "address1=$ip/32,$gateway" >> $nm_config
+            echo "addresses1=$ip;32;$gateway" >> $nm_config
         else
-            echo "address1=$ip/32" >> $nm_config
+            echo "addresses1=$ip;32" >> $nm_config
         fi
         chmod 600 $nm_config
     fi