Remove ununsed CONTRIBUTING link on edit MR form.

The code is never reached because the new and edit MR forms have diverged,
and the CONTRIBUTING link is not shown when editing MRs.
Add bugzilla to list because people ask about it.
Use new version of gitlab_git with extended rugged usage
Add unixsocketperm note to upgrade guide
Improve diff and bump gitlab_git revision
Add missing Redis item list in Overview [ci skip].
Merge pull request #7847 from axilleas/doc_install_redis

Add missing Redis item list in installation.md#overview
Fix the sed command for increasing the backlog
set the proposed backup time to 4am
Merge branch 'sed_backlog' into 'master'

Sed backlog

See merge request !1117
Merge branch 'master' of github.com:gitlabhq/gitlabhq
Merge branch 'backup-time' into 'master'

Backup time

The suggested backup time conflicts with daylight savings time, which occurs between 1-3am, causing the backup either to be skipped or ran twice.

See merge request !1118
Decorate commit parents

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Rollback diff drop and set default commit id to HEAD

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fix wiki

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fix 'Invalid socket file permissions' error
Fix 500 error on empty search in project

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fix graphs

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fix Commit stats and diff encoding issues

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fix security tests

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>