Don't generate adjacent links in wp_head() for attachments.

props kovshenin.
fixes #21658.
Built from https://develop.svn.wordpress.org/trunk@28770


git-svn-id: http://core.svn.wordpress.org/trunk@28583 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/link-template.php

@@ -1655,7 +1655,7 @@ function adjacent_posts_rel_link( $title = '%title', $in_same_term = false, $exc
  *
  */
 function adjacent_posts_rel_link_wp_head() {
-	if ( ! is_single() ) {
+	if ( ! is_single() || is_attachment() ) {
 		return;
 	}
 	adjacent_posts_rel_link();

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.0-alpha-20140617';
+$wp_version = '4.0-alpha-20140618';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.