Increased vertical alignment of labels for issues in lists

## What does this MR do?

Increases the vertical alignment between labels on issues in issue boards lists.

## Screenshots (if relevant)

![Screen_Shot_2016-08-19_at_16.05.31](/uploads/4edc0fa520d1a0bf692d42d5f99ce4d7/Screen_Shot_2016-08-19_at_16.05.31.png)

See merge request !5902