Merge branch 'update-spring-to-1.7.2' into 'master'

Update spring to 1.7.2 to fix hanging rails console

## What does this MR do?
Update spring to 1.7.2.

## Why was this MR needed?
This fixes hanging rails console issue.

## Related
Fixes https://gitlab.com/gitlab-org/gitlab-development-kit/issues/127

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry 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 [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5066

Gemfile.lock

@@ -692,7 +692,7 @@ GEM
       spinach (>= 0.4)
     spinach-rerun-reporter (0.0.2)
       spinach (~> 0.8)
-    spring (1.7.1)
+    spring (1.7.2)
     spring-commands-rspec (1.0.4)
       spring (>= 0.9.1)
     spring-commands-spinach (1.1.0)