Index: wp-admin/includes/media.php
===================================================================
--- wp-admin/includes/media.php	(revision 20376)
+++ wp-admin/includes/media.php	(working copy)
@@ -171,7 +171,7 @@
 		$s = preg_replace( '/[\r\n\t]+/', ' ', $str[0] );
 		// look for single quotes inside html attributes (for example in title)
 		$s = preg_replace_callback( '/="[^"]+"/', '_cleanup_image_add_caption2', $s );
-		return str_replace(	'"', "'", $s );
+		return str_replace( '"', "'", $s );
 	}
 
 	return '';