NX server: Correct message queue names. Should not be at /dev, but rather relative to /var/mqueue.

fs/mqueue/mq_open.c

@@ -100,12 +100,21 @@ mqd_t mq_open(FAR const char *mq_name, int oflags, ...)
 
   /* Make sure that a non-NULL name is supplied */
 
-  if (!mq_name)
+  if (mq_name == NULL || *mq_name == '/0')
     {
       errcode = EINVAL;
       goto errout;
     }
 
+  /* Skip over any leading '/'.  All message queue paths are relative to
+   * CONFIG_FS_MQUEUE_MPATH.
+   */
+
+  while (*mq_name == '/')
+    {
+      mq_name++;
+    }
+
   /* Get the full path to the message queue */
 
   snprintf(fullpath, MAX_MQUEUE_PATH, CONFIG_FS_MQUEUE_MPATH "/%s", mq_name);