Fix stray variable in FetchGitRepositoryUrls, a=chris

diff --git a/src/library/FetchGitRepositoryUrls.php b/src/library/FetchGitRepositoryUrls.php
index 1d5e88fb8..6fb7ddd02 100755
--- a/src/library/FetchGitRepositoryUrls.php
+++ b/src/library/FetchGitRepositoryUrls.php
@@ -210,7 +210,6 @@ class FetchGitRepositoryUrls implements CrawlConstants
      */
     public static function checkForRepository($extension)
     {
-        $repository_type;
         if (isset(self::$repository_types[$extension])) {
             $repository_type = self::$repository_types[$extension];
         } else {