About page: Fix jQuery version # and decouple this from the string, as we had done in WP 3.3. see #24832.

Merges [24900] to the 3.6 branch.



git-svn-id: https://core.svn.wordpress.org/branches/3.6@24901 1a063a9b-81f0-0310-95a4-ce76da25c4cd