Currently, if writing out a log entry fails, we unlink that log entry from our internal list of logfiles. So if writev(2) fails for potentially transient errors like ENOSPC, syslogd requires a restart, even if the filesystem has purged.
Currently, if writing out a log entry fails, we unlink that log entry from our
internal list of logfiles. So if writev(2) fails for potentially transient
errors like ENOSPC, syslogd requires a restart, even if the filesystem has
purged.

This change allows syslogd to ignore ENOSPC space errors, so that when the
filesystem is cleaned up, syslogd will automatically start logging again
without requiring the reset. This makes syslogd(8) a bit more reliable.

MFC after:	1 week

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase