Fix internal snippets

See merge request !1216

Conflicts:
	CHANGELOG

Fix 500 error on login page if ldap enabled and sign-in disabled

Related to gitlab/gitlabhq#1701

See merge request !1209

Fix ldap check [stable]

Fix ldap check for stable branch

See merge request !1208

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

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

Error messages fix

See merge request !1201

[7.4 rc fix] [doc] clarify when database.yml needs to be updated

[7.4 rc fix] [doc] stop gitlab before mysql optimizations, run checks

[7.4 rc fix] [doc] actually give command necessary to update unicorn

[7.4 rc fix] [doc] stop gitlab before backup

[7.4 rc fix] [doc] add missing configure Redis to use sockets

[7.4 rc fix] [doc] add optimizations for mysql to 6.x->7.4 guide

Fixes from master

It includes:

* https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/1193
* https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/1196
* https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/1195

See merge request !1198

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

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

We need to skip empty repositories when creating a backup. Before this
change, we were asking gollum-lib if the wiki contains any _pages_. Now
we ask gitlab_git if the repository contains _files_. This should
resolve gollum_lib Grit timeouts in the backup script.

Add mysql optimizations from 7.3-to-7.4.md.

Add details from 7.2-to-7.3.md. Replaces https://github.com/gitlabhq/gitlabhq/pull/8047.

Stopping gitlab before backup ensures that backup has everything before upgrade incase something goes wrong. Also remove extra cd.

Give command to update unicorn.rb rather than just say you need to do it.

Update MySQL optimizations to reflect doing updates after GitLab has already been started back up.