caching: output error on invalid action param

for bootstrap, the check is moved to the case statement for greater
robustness, and for consistency with other scripts.

Gbp-Dch: Ignore

scripts/build/bootstrap_cache

@@ -21,11 +21,6 @@ USAGE="${PROGRAM} {restore|save} [--force]"
 _ACTION="${1}"
 shift
 
-if ! In_list "${_ACTION}" restore save; then
-	Echo_error "Invalid action parameter"
-	exit 1
-fi
-
 # Processing arguments and configuration files
 Init_config_data "${@}"
 
@@ -98,4 +93,9 @@ case "${_ACTION}" in
 		# Creating stage file
 		Create_stagefile "${STAGE_FILE}"
 		;;
+
+	*)
+		Echo_error "Invalid action parameter: '${_ACTION}'"
+		Usage --fail
+		;;
 esac

scripts/build/chroot_cache

@@ -76,4 +76,9 @@ case "${_ACTION}" in
 		# Creating stage file
 		Create_stagefile "${STAGE_FILE}"
 		;;
+
+	*)
+		Echo_error "Invalid action parameter: '${_ACTION}'"
+		Usage --fail
+		;;
 esac