Update the end_token correctly, otherwise the token doesn't advance and the client gets duplicate events

SYN-377: Make sure that the event is marked as persisted from the main thread.

SYN-377: Make sure that the StreamIdGenerator.get_next.__exit__ is called from the main thread after the transaction completes, not from database thread before the transaction completes.

Fix 500 on push rule updates.

Hotfixes v0.9.0 r3