Fix parse error in PHP 5.2.

props georgestephanis.
see #20276.
Built from https://develop.svn.wordpress.org/trunk@29222


git-svn-id: http://core.svn.wordpress.org/trunk@29006 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Update some inline docs for the `WP_Http` class. Fixes #28943.
Built from https://develop.svn.wordpress.org/trunk@29223


git-svn-id: http://core.svn.wordpress.org/trunk@29007 1a063a9b-81f0-0310-95a4-ce76da25c4cd