Use non-zero timeout in update method and don't ignore exceptions.

Timeout in update method was set to 0 which doesn't mean no timeout.
As a result update might not work on loaded systems or slow network.
Also timeout exception was silently ignored.
Now sreq.send() is used in the same way as in other methods.
Add support for mine in masterless configuration.
Merge pull request #8106 from zeezooz/fix_mine_timeout

Use non-zero timeout in mine.update method and don't ignore exceptions.