Merge branch 'update-rake-docs-for-omnibus-assets' into 'master'

Update maintenance documentation to explain no need to recompile asssets for omnibus installations

See merge request !847

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 
 v 7.13.0 (unreleased)
+  - Update maintenance documentation to explain no need to recompile asssets for omnibus installations (Stan Hu)
   - Support commenting on diffs in side-by-side mode (Stan Hu)
   - Fix JavaScript error when clicking on the comment button on a diff line that has a comment already (Stan Hu)
   - Remove project visibility icons from dashboard projects list

doc/raketasks/maintenance.md

@@ -165,13 +165,18 @@ sudo -u git -H bundle exec rake cache:clear RAILS_ENV=production
 Sometimes during version upgrades you might end up with some wrong CSS or
 missing some icons. In that case, try to precompile the assets again.
 
-For Omnibus-packages:
-```
-sudo gitlab-rake assets:precompile
-```
+Note that this only applies to source installations and does NOT apply to
+omnibus packages.
 
 For installations from source:
 ```
 cd /home/git/gitlab
 sudo -u git -H bundle exec rake assets:precompile RAILS_ENV=production
 ```
+
+For omnibus versions, the unoptimized assets (JavaScript, CSS) are frozen at
+the release of upstream GitLab. The omnibus version includes optimized versions
+of those assets. Unless you are modifying the JavaScript / CSS code on your
+production machine after installing the package, there should be no reason to redo
+rake assets:precompile on the production machine. If you suspect that assets
+have been corrupted, you should reinstall the omnibus package.