Twenty Twelve: add back missing space in CSS value, removed in r24013. See #23790.

git-svn-id: http://core.svn.wordpress.org/trunk@24014 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Use get_post_format() instead of assuming we already have it.

* Fixes an issue where image posts without a title could not be deleted

fixes #23887. see #24046. props WraithKenny, SergeyBiryukov.

git-svn-id: http://core.svn.wordpress.org/trunk@24015 1a063a9b-81f0-0310-95a4-ce76da25c4cd