Fix worker error when remove branch

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fix typo in push service

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Improve git_push service specs

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'fix-branch-rm' into 'master'

Fix branch removal

Fix exception on post-receive worker when remove branch

See merge request !1122
Merge branch 'master' of github.com:gitlabhq/gitlabhq