Same strategy with:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/17810

See:
https://stackoverflow.com/a/29710188/1992201

Frankly I don't really understand how this works and I don't really
care either. However I tried it and it does the job. To try this,
make sure you have pending migrations, and run the server, hit the site.
It would tell you that there's pending migrations, and then run
migrations, and then hit the site again.

Without this patch, Rails would complain that "A copy of ...",
with this patch, it works without problems.

This reverts merge request !17159

Right now Project::VariablesController users the `value` parameter to send the
secret variable value. `value` is a pretty generic term and could be used in
other controllers, but for now it's better to err on the side of caution and
filter this out.

Closes #43313

This fixes an issue where the Rails autoload system would throw various `Unable to autoload constant` errors (such as `Unable to autoload constant EE::ProjectsHelper`) when using the autoload system (such with `spring` or `reload!` in the rails console.

This error was specifically ocurring in the EE code, however, it's seems reasonable to place the fix in CE as a general innoculation.