mohqueue: fixed db_qtable parameter name

- reported by Marino Mileti

modules/mohqueue/mohq.c

@@ -70,7 +70,7 @@ int moh_maxcalls = 50;
 static param_export_t mod_parms [] = {
   { "db_url", PARAM_STR, &db_url },
   { "db_ctable", PARAM_STR, &db_ctable },
-  { "db_ctable", PARAM_STR, &db_qtable },
+  { "db_qtable", PARAM_STR, &db_qtable },
   { "mohdir", PARAM_STRING, &mohdir },
   { "moh_maxcalls", INT_PARAM, &moh_maxcalls },
   { NULL, 0, NULL },