Update documentation according to the new multiple git mount points feature

doc/administration/repository_storages.md

 # Repository storages
 GitLab allows you to define repository storage paths to enable distribution of
-storage load between several mount points.
+storage load between several mount points. You can choose where new projects are
+stored via the `Application Settings` in the Admin interface.
 ## For installations from source

doc/raketasks/cleanup.md

@@ -2,7 +2,7 @@
 ## Remove garbage from filesystem. Important! Data loss!
-Remove namespaces(dirs) from `/home/git/repositories` if they don't exist in GitLab database.
+Remove namespaces(dirs) from all repository storage paths if they don't exist in GitLab database.
 ```
 # omnibus-gitlab
@@ -12,7 +12,7 @@ sudo gitlab-rake gitlab:cleanup:dirs
 bundle exec rake gitlab:cleanup:dirs RAILS_ENV=production
 ```
-Rename repositories from `/home/git/repositories` if they don't exist in GitLab database.
+Rename repositories from all repository storage paths if they don't exist in GitLab database.
 The repositories get a `+orphaned+TIMESTAMP` suffix so that they cannot block new repositories from being created.
 ```