WIP: Fix of 'Commits being passed to custom hooks are already reachable when using the UI'

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/19771 This MR changes the way how we create commit, we create it directly in the branch and we don't use temporary ref anymore. This also works similar to how git-receive-pack works so it's a natural way to create commit.

• Replace reference to gitlab_git gem in Gemfile when one released with our change (https://gitlab.com/gitlab-org/gitlab_git/merge_requests/102)
• Specs
• Fix CreateBranchService
• Back-port to CE (https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5337)

Added 1 commit:

• 098486e7 - Fix create branch service

Added 1 commit:

• 04348e02 - Fix of 'Commits being passed to custom hooks already reachable when using the UI'

Added 24 commits:

• 04348e02...1c04b072 - 23 commits from branch master
• d272eda5 - Fix of 'Commits being passed to custom hooks already reachable when using the UI'

Marked the task Fix CreateBranchService as completed

Added 1 commit:

• cfbd8d81 - Fix of 'Commits being passed to custom hooks already reachable when using the UI'

Added 14 commits:

• cfbd8d81...8bfb7369 - 13 commits from branch master
• 3ef1bb48 - Fix of 'Commits being passed to custom hooks already reachable when using the UI'

Marked the task Specs as completed

Reassigned to @dzaporozhets

@dzaporozhets Please review. Specs are failing because rubocop does not like Gemfile, I will revert it anyway when gitlab_git MR is merged. So nevermind.

@vsizov looks good to me.

Added 1 commit:

• 7cf6f50f - Fix of 'Commits being passed to custom hooks already reachable when using the UI'

Marked the task Replace reference to gitlab_git gem in Gemfile when one released with our change (https://gitlab.com/gitlab-org/gitlab_git/merge_requests/102) as completed

Marked the task Back-port to CE as completed

Reassigned to @vsizov

I back-ported this to CE then:

• merge
• merge CE->EE
• rebase this MR against master
• apply EE specific changes from this MR

Status changed to merged

Milestone changed to %8.11