Improve readability of environments table

## What does this MR do?
Fix the environments table columns width

## Before
![Screen_Shot_2016-11-21_at_18.13.00](/uploads/1771b0546eb3cb15f4894b719fd44286/Screen_Shot_2016-11-21_at_18.13.00.png)

## After
![Screen_Shot_2016-11-21_at_18.11.18](/uploads/a20194a055b6ec0f7989f0c1499883d3/Screen_Shot_2016-11-21_at_18.11.18.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
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] 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 !7628