Change Github.com repo from "Mirror Repository" to "Remote Mirror Repository"

Hi,

I'm currently trying to shift main development of the Open Source npm modules of my company Lossless GmbH (https://www.npmjs.com/~lossless) from GitHub.com to GitLab.com

I'm importing all the repos from GitHub, however when I try to switch off Mirror Repository and switch on Remote Mirror Repository with the original GitHub URL I get an error saying: Remote mirrors url is already in use

Here is one of the repos this fails with: https://gitlab.com/pushrocks/npmts