set default value for isPresenter in case user removed

bigbluebutton-html5/imports/ui/components/actions-bar/service.js

@@ -25,9 +25,9 @@ const takePresenterRole = () => makeCall('assignPresenter', Auth.userID);
 
 export default {
   amIPresenter: () => Users.findOne({ userId: Auth.userID },
-    { fields: { presenter: 1 } }).presenter,
+    { fields: { presenter: 1 } }).presenter || false,
   amIModerator: () => Users.findOne({ userId: Auth.userID },
-    { fields: { role: 1 } }).role === ROLE_MODERATOR,
+    { fields: { role: 1 } }).role === ROLE_MODERATOR || false,
   meetingName: () => Meetings.findOne({ meetingId: Auth.meetingID },
     { fields: { 'meetingProp.name': 1 } }).meetingProp.name,
   users: () => Users.find({