test: Add image-prepare --network option

This is useful for experimentation.

test/image-prepare

@@ -233,11 +233,15 @@ def main():
     parser.add_argument('-q', '--quick', action='store_true', help='Skip unit tests to build faster')
     parser.add_argument('-o', '--overlay', action='store_true',
                         help='Install into existing test/image/ overlay instead of from pristine base image')
+    parser.add_argument('--network', action='store_true',
+                        help='Enable internet access (only for local experiments, not for production!)')
     parser.add_argument('--container', action='store_true', help='Install cockpit/ws container instead of rpms')
     parser.add_argument('image', nargs='?', default=DEFAULT_IMAGE, help='The image to use')
     args = parser.parse_args()
 
-    customize = [os.path.join(BOTS_DIR, "image-customize"), "--no-network"]
+    customize = [os.path.join(BOTS_DIR, "image-customize")]
+    if not args.network:
+        customize.append("--no-network")
     if not args.overlay:
         customize.append("--fresh")
     if args.verbose: