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.

Clarify that database.yml should be updated if you are running a MySQL Database. Remove wording that de-emphasises importance of update.

Merge master into 7-4-stable

See merge request !1189

Fix user being blocked after oauth sign-in

See merge request !1190

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

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

Issue respect single sign on

Adds regression test for #1677

See merge request !1188

verification for #1677

Since testing omniauth_callback_controller.rb is very difficult, the logic
is moved to the models

This is handled within the LDAP class

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

Add a few items to changelog

See merge request !1187

Issue respect single sign on

Fixes #1677 by making sure the per-build user is saved as well. Otherwise the user is passed to devise, and the user is saved afterwards, creating a successful signup.

See merge request !1186

Because devise will trigger a save, allowing unsaved users to login, behaviour had changed.
The current implementation returns a pre-build user, which can be saved without errors.

Reported in #1677

Fix link to githost.io

Documentation pointed to wrong gitlab-ci project.

See merge request !222

Note omnibus in installation

See merge request !1184