syslogd: Ignore getaddrinfo() errors if -ss is specified

This can arise if the jail doesn't have networking configured, and if
-ss is specified, syslogd won't listen on port 514 anyway.

Add a regression test case for this as well.

PR: 238006
MFC after: 1 month

(cherry picked from commit 5d045d556b1cfeb1487d49017b536afb3df105d3)