User can see the deleted message via direct link

User can open deleted message in case he saved the direct link.

Steps:

1. Send private message and open it from Outbox. Copy link (save the link somehow)
2. Delete this message
3. Paste saved link to the browser.

As a result, message is opened.
Expected, that message in unavailable for user in case he removes the message.

Possible use case:
There are 2 registered users. They use common computer.
1. User1 wrote a PM to User2.
2. User1 deleted this PM from the list of outgoing message, and didn't logout.
3. User2 received a notice in the e-mail and clicked the link.

Actual result: The deleted message is opened.
Expected result: The "error 404" message is opened.

!note!:
1. If the User1 deleted opened message, then message deleted from incoming list of User2.