log error in streamError instead of creating new one

Author: Fred K. Schott

lib/memcached.js

@@ -162,7 +162,7 @@ Client.config = {
             var metaData = S.metaData.shift();
             if (metaData && metaData.callback){
                 metaData.execution = Date.now() - metaData.start;
-                memcached.delegateCallback(metaData, new Error('Stream error'), false, metaData.callback);
+                memcached.delegateCallback(metaData, e, false, metaData.callback);
             }
         };