WP_HTTP: Prevent the 'max_body_length' and 'stream_handle' properties of the curl class from leaking between requests by specifically initializing them in every case. See #23472 & r23605


git-svn-id: http://core.svn.wordpress.org/trunk@23609 1a063a9b-81f0-0310-95a4-ce76da25c4cd