1. Create an Account with GitLab
2. Switch to email sign in
3. Go to Account Settings > Security
Observed: No option to switch account to GitLab login
Expected: The option to switch login methods should be there if more than one login method is enabled.
Note: I think that might be what was causing some of the issues people were hitting here - http://forum.mattermost.org/t/sign-in-method-option-unavailable-after-gitlab-8-9-upgrade/1822/10