9722 fix alignment of event items and its children

Created by: trimentor

Issue: https://github.com/gitlabhq/gitlabhq/issues/9722

Could reproduce the issue on:

• GitLab Community Edition 8.1.2 <4e54222>
• gitlab-development-kit

How to reproduce:

1. Navigate to "/dashboard/activity" on a tablet in portrait mode or resize your desktop's browser window to a width of "768px".
2. Push code to a branch with a long name
3. A combination of a long first line (mentioning the name of your branch) and a timeago value of "about an hour ago" will push the first line downwards