fix: [vps] make ``vps install backup`` work on dev installs

bin/vps

@@ -1460,9 +1460,6 @@ cmdline.spec:install:cmd:compose-backup:run() {
     : :optval: --service-name,-s   "YAML service name in compose
                                     file to check for existence of key.
                                     Defaults to '$DEFAULT_BACKUP_SERVICE_NAME'"
-    : :optval: --compose-file,-f   "Compose file location. Defaults to
-                                    the value of '\$DEFAULT_COMPOSE_FILE'"
-
     : :optfla: --ignore-domain-check \
                                    "Allow to bypass the domain check in
                                     compose file."
@@ -1474,8 +1471,8 @@ cmdline.spec:install:cmd:compose-backup:run() {
 
     [ -e "/etc/compose/local.conf" ] && source /etc/compose/local.conf
 
-    compose_file=${opt_compose_file:-$DEFAULT_COMPOSE_FILE}
     service_name=${opt_service_name:-$DEFAULT_BACKUP_SERVICE_NAME}
+    compose_file=$(compose:get-compose-yml) || return 1
 
     if ! [ -e "$compose_file" ]; then
         err "Compose file not found in '$compose_file'."