Merge branch 'issuable-form-alignment' into 'master'

Fixed alignment on issuable new form

Fixes #13802

![Screen_Shot_2016-04-11_at_17.03.29](/uploads/d359580e693284d4b694d8158d4f736e/Screen_Shot_2016-04-11_at_17.03.29.png)

See merge request !3661