Merge branch 'correct-slack-slash-commands-pretty-path' into 'master'

Correct mattermost slash commands pretty path

## What does this MR do?

Corrects the pretty path used for mattermost slash commands.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

## Screenshots (if relevant)

![Screen_Shot_2016-12-14_at_13.31.18](/uploads/61b0cbe11bf747d566ed7959efa704b8/Screen_Shot_2016-12-14_at_13.31.18.png)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !8085

app/views/projects/services/mattermost_slash_commands/_help.html.haml

-- pretty_path_with_namespace = "#{@project ? @project.namespace.name : 'namespace'} / #{@project ? @project.name : 'name'}"
-- run_actions_text = "Perform common operations on this project: #{pretty_path_with_namespace}"
+- run_actions_text = "Perform common operations on this project: #{@project.name_with_namespace}"
 
 .well
   This service allows GitLab users to perform common operations on this
@@ -27,7 +26,7 @@
     .form-group
       = label_tag :display_name, 'Display name', class: 'col-sm-2 col-xs-12 control-label'
       .col-sm-10.col-xs-12.input-group
-        = text_field_tag :display_name, "GitLab / #{pretty_path_with_namespace}", class: 'form-control input-sm', readonly: 'readonly'
+        = text_field_tag :display_name, "GitLab / #{@project.name_with_namespace}", class: 'form-control input-sm', readonly: 'readonly'
         .input-group-btn
           = clipboard_button(clipboard_target: '#display_name')