Verifying the peer name on the X509 Certs correctly.

- The SANs take precedence over the CN.
- The CN is only checked if there are no SANs.
- Fixing the tests as the test cert did not list *.test.google.com in
  the SANs. Will fix the test cert another time...
diff --git a/src/php/tests/interop/interop_client.php b/src/php/tests/interop/interop_client.php
index 5a09fc7..82ca438 100755
--- a/src/php/tests/interop/interop_client.php
+++ b/src/php/tests/interop/interop_client.php
@@ -215,7 +215,7 @@
     new Grpc\BaseStub(
         $server_address,
         [
-            'grpc.ssl_target_name_override' => 'foo.test.google.com',
+            'grpc.ssl_target_name_override' => 'foo.test.google.fr',
             'credentials' => $credentials
          ]));