#2 nsca exits on ECONNABORTED

[Craig Leres]

We've had a lot of issues on our FreeBSD 9 systems with the nsca daemon exiting due to ECONNABORTED. This is probably cuased by cyber security scanning tickling a race condition in nsca itself.

The FreeBSD accept(2) man page says:

 [ECONNABORTED]     A connection arrived, but it was closed
                    while waiting on the listen queue.

A mimimal patch is attached. A better fix would be to never treat accept(2) errors as fatal.