Use array_replace_recursive for context values

A context array, user and password passed to constructor is leading to duplicated values for the context options.

lib/Horde/ManageSieve.php

@@ -273,7 +273,7 @@ public function connect(
             $this->_params['port'] = $port;
         }
         if (isset($context)) {
-            $this->_params['context'] = array_merge_recursive(
+            $this->_params['context'] = array_replace_recursive(
                 $this->_params['context'],
                 $context
             );