After editing the poll voted users cannot vote again.

After editing the poll vote results reset and already voted users cannot vote again

Steps to reproduce:
1. Sign in JCommune.
2. Select any Branch and create the Topic with poll.
3. Fill out topic using the data #1 below:

Data #1
Topiс title: Topic_1
Message content: This is message
Poll: Poll_1
Option list:
Item_1
Item_2
Multiple answers are allowed: don't check
Ending date: don't set

4. Click the "Save" button.
5. Select the topic you have just created (Topic_1) and vote on the Poll.
6. Log out from the Forum.
7. Register a new user (User #2), go to the Topic_1 and vote on the same poll.
8. Log out and log in via User #1.
9. Go to the Topic_1.
10. Click "Edit" button and change the data using the data #2 below:

Data #2
Topiс title: Topic_1
Message content: This is message
Poll: Poll_1+
Option list:
Item_1+
Item_2+
Multiple answers are allowed: don't check
Ending date: don't set

11. Click the "Save" button.
12. Select the Topic_1 and vote on the Poll again.
13. Log out from the Forum.
14. Log into the Forum using User #2, select the Topic_1 and vote on the Poll again.

Actual Result: After editing the poll the previous voting results were removed. You can't re-vote on the poll using the User #1 and #2.
Expected Result: After editing the poll the previous voting results were removed and you have successfully re-voted using the User # 1 and #2.