Fix the 8.17 to 9.0 upgrade guide

Install gitlab-shell and gitlab-workhorse after updating the code, and
update configuration files before installing libs, migrations etc.

[ci skip]
Signed-off-by: Rémy Coutable <remy@rymai.me>

doc/update/8.17-to-9.0.md

@@ -97,62 +97,32 @@ cd /home/git/gitlab
 sudo -u git -H git checkout 9-0-stable-ee
 ```
 
-### 6. Install libs, migrations, etc.
+### 6. Update gitlab-shell
 
 ```bash
-cd /home/git/gitlab
-
-# MySQL installations (note: the line below states '--without postgres')
-sudo -u git -H bundle install --without postgres development test --deployment
-
-# PostgreSQL installations (note: the line below states '--without mysql')
-sudo -u git -H bundle install --without mysql development test --deployment
-
-# Optional: clean up old gems
-sudo -u git -H bundle clean
-
-# Run database migrations
-sudo -u git -H bundle exec rake db:migrate RAILS_ENV=production
-
-# Update node dependencies and recompile assets
-sudo -u git -H bundle exec rake yarn:install gitlab:assets:clean gitlab:assets:compile RAILS_ENV=production NODE_ENV=production
+cd /home/git/gitlab-shell
 
-# Clean up cache
-sudo -u git -H bundle exec rake cache:clear RAILS_ENV=production
+sudo -u git -H git fetch --all --tags
+sudo -u git -H git checkout v$(</home/git/gitlab/GITLAB_SHELL_VERSION)
 ```
 
-**MySQL installations**: Run through the `MySQL strings limits` and `Tables and data conversion to utf8mb4` [tasks](../install/database_mysql.md).
-
 ### 7. Update gitlab-workhorse
 
 Install and compile gitlab-workhorse. This requires
 [Go 1.5](https://golang.org/dl) which should already be on your system from
-GitLab 8.1.
-
-```bash
-cd /home/git/gitlab
-
-sudo -u git -H bundle exec rake "gitlab:workhorse:install[/home/git/gitlab-workhorse]" RAILS_ENV=production
-```
-
-### 8. Update gitlab-shell
+GitLab 8.1. GitLab-Workhorse uses [GNU Make](https://www.gnu.org/software/make/).
+If you are not using Linux you may have to run `gmake` instead of
+`make` below.
 
 ```bash
-cd /home/git/gitlab-shell
+cd /home/git/gitlab-workhorse
 
 sudo -u git -H git fetch --all --tags
-sudo -u git -H git checkout v5.0.0
+sudo -u git -H git checkout v$(</home/git/gitlab/GITLAB_WORKHORSE_VERSION)
+sudo -u git -H make
 ```
 
-### 9. Optional: install Gitaly
-
-Gitaly is still an optional component of GitLab. If you want to save time
-during your 9.0 upgrade **you can skip this step**.
-
-If you do want to set up Gitaly in GitLab 9.0 then follow [Gitaly section of the installation
-guide](https://gitlab.com/gitlab-org/gitlab-ce/blob/9-0-stable/doc/install/installation.md#install-gitaly).
-
-### 10. Update configuration files
+### 8. Update configuration files
 
 #### New configuration options for `gitlab.yml`
 
@@ -289,6 +259,40 @@ For Ubuntu 16.04.1 LTS:
 sudo systemctl daemon-reload
 ```
 
+### 9. Install libs, migrations, etc.
+
+```bash
+cd /home/git/gitlab
+
+# MySQL installations (note: the line below states '--without postgres')
+sudo -u git -H bundle install --without postgres development test --deployment
+
+# PostgreSQL installations (note: the line below states '--without mysql')
+sudo -u git -H bundle install --without mysql development test --deployment
+
+# Optional: clean up old gems
+sudo -u git -H bundle clean
+
+# Run database migrations
+sudo -u git -H bundle exec rake db:migrate RAILS_ENV=production
+
+# Update node dependencies and recompile assets
+sudo -u git -H bundle exec rake yarn:install gitlab:assets:clean gitlab:assets:compile RAILS_ENV=production NODE_ENV=production
+
+# Clean up cache
+sudo -u git -H bundle exec rake cache:clear RAILS_ENV=production
+```
+
+**MySQL installations**: Run through the `MySQL strings limits` and `Tables and data conversion to utf8mb4` [tasks](../install/database_mysql.md).
+
+### 10. Optional: install Gitaly
+
+Gitaly is still an optional component of GitLab. If you want to save time
+during your 9.0 upgrade **you can skip this step**.
+
+If you do want to set up Gitaly in GitLab 9.0 then follow [Gitaly section of the installation
+guide](../install/installation.md#install-gitaly).
+
 ### 11. Start application
 
 ```bash