Twenty Twelve always trumps its pretenders. see #19978.

git-svn-id: https://develop.svn.wordpress.org/trunk@19969 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/theme.php

@@ -396,14 +396,14 @@ function get_themes() {
 		// Check for theme name collision. This occurs if a theme is copied to
 		// a new theme directory and the theme header is not updated. Whichever
 		// theme is first keeps the name. Subsequent themes get a suffix applied.
-		// The Twenty Eleven, Twenty Ten, Default and Classic themes always trump
-		// their pretenders.
+		// Default themes themes always trump their pretenders.
 		if ( isset($wp_themes[$name]) ) {
 			$trump_cards = array(
 				'classic'      => 'WordPress Classic',
 				'default'      => 'WordPress Default',
 				'twentyten'    => 'Twenty Ten',
 				'twentyeleven' => 'Twenty Eleven',
+				'twentytwelve' => 'Twenty Twelve',
 			);
 			if ( isset( $trump_cards[ $stylesheet ] ) && $name == $trump_cards[ $stylesheet ] ) {
 				// If another theme has claimed to be one of our default themes, move