wp-caption-text class for the gallery shortcode caption. props chipbennett, fixes #14411.

git-svn-id: https://develop.svn.wordpress.org/trunk@16864 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/media.php

@@ -854,7 +854,7 @@ function gallery_shortcode($attr) {
 			</{$icontag}>";
 		if ( $captiontag && trim($attachment->post_excerpt) ) {
 			$output .= "
-				<{$captiontag} class='gallery-caption'>
+				<{$captiontag} class='wp-caption-text gallery-caption'>
 				" . wptexturize($attachment->post_excerpt) . "
 				</{$captiontag}>";
 		}