Do not allow mpcdf_enable_repositories for images

mpcdf_enable_repositories.py

@@ -71,6 +71,9 @@ def do_mpcdf_enable_repositories(self, subcmd, opts, *args):
     else:
         raise osc.oscerr.WrongArgs("Too many arguments")
 
+    if project.startswith("images"):
+        raise osc.oscerr.WrongArgs("This function is not available for packages in 'images'")
+
     api_url = self.get_api_url()
 
     if opts.disable: