Fixes #8626: ensure errata icons line up, BZ 1171310.

The errata icons were not lining up on the list and
details pages.  This commit ensures that they line up,
thus enhancing readability.

http://projects.theforeman.org/issues/8626
https://bugzilla.redhat.com/show_bug.cgi?id=1171310
Merge pull request #4862 from waldenraines/8626

Fixes #8626: ensure errata icons line up, BZ 1171310.