Fix alignment and borders of plugin/theme updates on the Updates screen.

props morganestes, ocean90.
see #26699, for trunk.

Built from https://develop.svn.wordpress.org/trunk@26935


git-svn-id: http://core.svn.wordpress.org/trunk@26816 1a063a9b-81f0-0310-95a4-ce76da25c4cd