Developers can push to wiki repo. Protected branches does not affect wiki repo any more

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Improve wiki path parsing in internal api

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'developer-can-push-wiki' into 'master'

Developer can push wiki

Fixes #1630

See merge request !1159
Merge branch 'master' of github.com:gitlabhq/gitlabhq