Add 'terminate_after' to Count endpoint whitelist (#634)

Closes #631

Author: brstgt

src/Elasticsearch/Endpoints/Count.php

@@ -72,7 +72,8 @@ public function getParamWhitelist()
             'lowercase_expanded_terms',
             'analyze_wildcard',
             'lenient',
-            'lowercase_expanded_terms'
+            'lowercase_expanded_terms',
+            'terminate_after'
         );
     }