Clears the password if user cancels password prompt.

Clears the password if user cancel attempt to enter password, as using one instance of locker for multiple attempts keeps the password.

modules/UI/authentication/RoomLocker.js

@@ -185,6 +185,10 @@ export default function createRoomLocker (room) {
                 newPass => { password = newPass; }
             ).catch(
                 reason => {
+                    // user canceled, no pass was entered.
+                    // clear, as if we use the same instance several times
+                    // pass stays between attempts
+                    password = null;
                     if (reason !== APP.UI.messageHandler.CANCEL)
                         console.error(reason);
                 }