luci-app-package-manager: fix 'Update lists' button for apk

Fix the button "Update lists..." to actually update package lists
instead of trying to upgrade all packages when using apk.
(No change for opkg.)

Note: the package upgrade button remains inactive with apk. It still
launches 'apk install' command, which does not work for upgrade.

Also remove whitespace from line end.

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>

applications/luci-app-package-manager/root/usr/libexec/package-manager-call

@@ -27,7 +27,7 @@ case "$action" in
 			find "${lists_dir:-/usr/lib/opkg/lists}" -type f '!' -name '*.sig' | xargs -r gzip -cd
 		fi
 	;;
-	install|update|remove)
+	install|update|upgrade|remove)
 		(
 			cmd="$ipkg_bin"
 
@@ -38,12 +38,15 @@ case "$action" in
 						action="add"
 					;;
 					update)
+						action="update"
+					;;
+					upgrade)
 						action="upgrade"
 					;;
 					remove)
 						action="del"
 					;;
-				esac							
+				esac
 			fi
 
 			# APK have --autoremove enabled by default and
@@ -104,7 +107,7 @@ case "$action" in
 		rm -f /tmp/ipkg.lock /tmp/ipkg.err /tmp/ipkg.out
 	;;
 	*)
-		echo "Usage: $0 {list-installed|list-available}"       >&2
+		echo "Usage: $0 {list-installed|list-available|update}" >&2
 		echo "       $0 {install|upgrade|remove} pkg[ pkg...]" >&2
 		exit 1
 	;;