Fix error with reopened merge request not properly reloading

If you reopen a Merge Request and then try to update the source branch
it won't properly reload the code since the "reload_code" method still
checks if the MR is "opened" and not just "open" (which includes reopened)
 Merge branch 'topic/fix_mr_reload_error' into '6-6-stable'

Fix reopened merge request's code reload