zypper: fix package removal

zypper only supports the --no-recommends option during installs, giving
the option during removals results in an error.

When setting ACTION=remove, remove --no-recommends from EXTRA_ARGS, and
set --clean-deps to also remove no-longer-needed dependencies.

Rename EXTRA_ARGS to ACTION_ARGS for increased readability.

Change-Id: Ifbd168992b1a20658b6b4a99ba175234f6c78f6d

diskimage_builder/elements/zypper/bin/install-packages

@@ -20,9 +20,9 @@ fi
 set -eu
 set -o pipefail
 
-EXTRA_ARGS="--no-recommends"
 MAP_ELEMENT=
 ACTION=install
+ACTION_ARGS="--no-recommends"
 
 SCRIPTNAME=$(basename $0)
 function show_options () {
@@ -48,8 +48,8 @@ eval set -- "$TEMP"
 while true ; do
     case "$1" in
         -u) run_zypper dist-upgrade --no-recommends; exit 0;;
-        -e) ACTION="remove"; shift;;
-        -d) EXTRA_ARGS="--download-only"; shift;;
+        -e) ACTION="remove"; ACTION_ARGS="--clean-deps"; shift;;
+        -d) ACTION_ARGS="${ACTION_ARGS} --download-only"; shift;;
         -m) MAP_ELEMENT=$2; shift 2;;
         -h) show_options;;
         --) shift; break ;;
@@ -68,5 +68,5 @@ fi
 if [ -z "${PKGS}" ]; then
     echo "Not running install-packages $ACTION with empty packages list"
 else
-    run_zypper $ACTION $EXTRA_ARGS $PKGS
+    run_zypper $ACTION $ACTION_ARGS $PKGS
 fi