Validate pingback source URIs. Less verbose errors.



git-svn-id: http://core.svn.wordpress.org/branches/3.5@23330 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Comment Query: Use $this->query_vars instead of the nonexistent shorthand $q.

Merges [23325] to the 3.5 branch.
fixes #23208.



git-svn-id: http://core.svn.wordpress.org/branches/3.5@23332 1a063a9b-81f0-0310-95a4-ce76da25c4cd