bug #513

[Кочура Иван]

Hello. My name is Kochura Ivan. I'm going to fixed a bug https://issues.
apache.org/jira/browse/OPENMEETINGS-513, using invatedHash. In addition to
the client id, we must preserve the InvitationHash in the RoomPollAnswers.
Based on the above, I have a question. How to get a InvitationHash if I
have only streamid. (in class PollService)