Twenty Eleven: ensure `twentyeleven_url_grabber()` is pluggable by wrapping in a `function_exists` check.

git-svn-id: https://develop.svn.wordpress.org/trunk@23474 602fd350-edb4-49c9-b593-d223f7449a82

wp-content/themes/twentyeleven/functions.php

@@ -458,6 +458,7 @@ function twentyeleven_content_nav( $html_id ) {
 }
 endif; // twentyeleven_content_nav
 
+if ( ! function_exists( 'twentyeleven_url_grabber' ) ) :
 /**
  * Return the URL for the first link found in the post content.
  *
@@ -470,6 +471,7 @@ function twentyeleven_url_grabber() {
 
 	return esc_url_raw( $matches[1] );
 }
+endif;
 
 /**
  * Count the number of footer sidebars to enable dynamic classes for the footer