Merge pull request #1924 from jitsi/status-message-clear

Skips showing empty statuses. Updates poltergeist to report connected.

modules/UI/UI.js

  * @param {string} status - The new status.
  */
 UI.updateUserStatus = (user, status) => {
+    if (!status) {
+        return;
+    }
+
     let displayName = user.getDisplayName();
     messageHandler.participantNotification(
         displayName, '', 'connected', "dialOut.statusMessage",

resources/prosody-plugins/mod_muc_poltergeist.lua

         -- we will mark it with ignore tag
         local nick = string.sub(username, 0, 8);
         if (have_poltergeist_occupant(room, nick)) then
+            -- notify that user connected using the poltergeist
+            update_poltergeist_occupant_status(
+                room, nick, "connected");
             remove_poltergeist_occupant(room, nick, true);
         end