"remote: Create merge request for branch" message requires Merge Request support to be enabled for fork

Problem description

Hi,

Unlike the people who commented in gitlab-ce#21451, I think the "remote: Create merge request for branch" message when pushing on the command line is very useful. I really want it to be there.

However, I noticed today that it was suddenly missing and I realized why: I have disabled merge requests for my fork of the upstream repo, since it's confusing (it will never contain any Merge Requests in my case, since all the MR:s are targetting the upstream fork).

So, to get this working I need to enable merge requests for my fork:

...and ensure this checkbox is not unchecked (it's checked by default):

Why this is a problem

This is a problem since all forks need to explicitly enable merge requests in their settings to be able to see this text, even though they might never ever receive a merge request in their fork anyway. Having an extra "Merge Requests" option in their fork repo can be a bit confusing, especially since it's all-empty and there is no easy way to go to the "Merge Requests for upstream repo".

I think it would be good to re-think this, even though I admit that this might be hard to get working with the current workflow. Just adding a link to the upstream repo in the fork-level "Merge requests" view could be a tolerable option.

Anyway, the way this currently works is a bit unintuitive for me, and perhaps for others as well; hence, suggesting the change.