Bump omniauth-gitlab to 1.0.2 to fix incompatibility with omniauth-oauth2
As noted in gitlab-com/support-forum#1270, omniauth-gitlab fails if omniauth-oauth2 is bumped to 1.4.0, OAuth2 quietly fails due to https://github.com/linchus/omniauth-gitlab/issues/10:
```
21:26:04 rails-web.1 | I, [2016-11-07T21:26:04.245007 #56637] INFO -- omniauth: (gitlab) Callback phase initiated.
21:26:05 rails-web.1 | E, [2016-11-07T21:26:05.068009 #56637] ERROR -- omniauth: (gitlab) Authentication failure! invalid_credentials: OAuth2::Error, invalid_grant: The provided authorization grant is invalid, expired, revoked, does not match the redirection URI used in the authorization request, or was issued to another client.
```
This was fixed and discussed here:
* 26c47e5539
* https://github.com/linchus/omniauth-gitlab/issues/10
Bumping this version to 1.0.2 will ensure future compatibility.
See merge request !7348
e671cd8995