Fix authentication issue with subversion 1.8

src/Composer/Util/Svn.php

@@ -112,7 +112,8 @@ class Svn
         // the error is not auth-related
         if (false === stripos($output, 'Could not authenticate to server:')
             && false === stripos($output, 'authorization failed')
-            && false === stripos($output, 'svn: E170001:')) {
+            && false === stripos($output, 'svn: E170001:')
+            && false === stripos($output, 'svn: E215004:')) {
             throw new \RuntimeException($output);
         }