fix(filter): Fixed multiple connections closing in Moira-Filter caused by PR-562.

[r9odt]

Fixed multiple connections closing in Moira Filter when closing one of the tcp connection.

PR Summary

A go-routine leak was fixed in PR-562, but it caused closing multiple connections when any of them were close. I guess that this is because a channel named handler.terminate is common to all goroutines, spawned in any instance of the handle function. When any data send to this channel, several goroutines receive them and closing their connection.

This PR suggests using an extra computation using the channel, named closeConnection to handle goroutine completion instead simple send any data into handler.terminate. This channel is local to each call to the handle function and the goroutine it spawns. Thus, when one connection will be closed, the goroutine, associated with the specific call to the handle function will complete and others continue work. Watching for closeConnection channel implemented via select block.

Additional information

Closes/Relates #issue

[coveralls]

Coverage decreased (-0.009%) to 80.919% when pulling a1ee597 on JIexa24:fix/fix_multiple_connection_closing_in_PR-562 into c2efd5d on moira-alert:master.