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
Could we do some sort of `table.errata-count` styling so that this doesn't introduce an ID and could be re-used elsewhere if needed in a table?