BacklinkCache was forgetting to check rd_interwiki when getting redirects, and thus getting

some extranous backlinks for the redirect table (if there happened to be a page redirecting
to an interwiki page with the same name plus an interwiki prefix).

Not a major issue since this is really only used as far as i can tell, to purge squids and html file cache.
A couple of extra unneeded purges shouldn't hurt anything, just a bit pointless.

RELEASE-NOTES-1.19

@@ -130,6 +130,8 @@ production.
 * Use content language in formatting of dates in revertpage message
   (rollback revert edit summary) and do not adjust for user timezone.
 * (bug 29277) MediaWiki:Filepage.css is also shown on the local wiki
+* Make sure Backlink cache does not retrieve interwiki redirects when looking for
+  redirects to a local page.
 
 === API changes in 1.19 ===
 * BREAKING CHANGE: action=watch now requires POST and token.

includes/BacklinkCache.php

@@ -207,10 +207,17 @@ class BacklinkCache {
 		switch ( $table ) {
 			case 'pagelinks':
 			case 'templatelinks':
+				$conds = array(
+					"{$prefix}_namespace" => $this->title->getNamespace(),
+					"{$prefix}_title"     => $this->title->getDBkey(),
+					"page_id={$prefix}_from"
+				);
+				break;
 			case 'redirect':
 				$conds = array(
 					"{$prefix}_namespace" => $this->title->getNamespace(),
 					"{$prefix}_title"     => $this->title->getDBkey(),
+					"{$prefix}_interwiki" => '',
 					"page_id={$prefix}_from"
 				);
 				break;