Allow for WP bug #23268

Ref: http://codex.wordpress.org/Class_Reference/WP_Query#Custom_Field_Parameters
Ref: http://core.trac.wordpress.org/ticket/23268

Found these while doing a quick search round for any other queries on meta values which may or may not account for the defaults no longer being saved. All those queries seemed to be fine at first glance.
Searched on `meta_query`, `meta_key` and `meta_value`.