bozo: do not fail silently on unknown bosserver options

bozo: do not fail silently on unknown bosserver options

Instead of failing silently when the bosserver is started with an
unknown option, print an error message and exit with a non-zero value.
Continue to exit with 0 when the -help option is given to request the
usage message.

This change should help make bosserver startup failures more obvious
when an unsupported option is specified. Example systemd status message:

   systemd[1]: Starting OpenAFS Server Service...
   bosserver[32308]: Unrecognized option: -bogus
   bosserver[32308]: Usage: bosserver [-noauth] ....
   systemd[1]: openafs-server.service: main process exited,
               code=exited, status=1/FAILURE

Reviewed-on: https://gerrit.openafs.org/12630
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit f5491119ff7d422b1c0c311a50e30bec1c15296c)

Change-Id: I5c3ffbb21915fd0a2773873e360cee85504796f8
Reviewed-on: https://gerrit.openafs.org/12631
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>