bozo: create a syslog connection only if the -syslog option is given

bozo: create a syslog connection only if the -syslog option is given

Fix a minor bug in which an unnecessary syslog connection is opened when
the BosLog is not present (typically, the first time the bosserver is
started) or when the BosLog is a named pipe, even if the -syslog option
was not given.

This bug was introduced in commit bdc7e43117706d0aa46d3b6435489e9d4c2b0888,
which added checks to avoid renaming logs when they are named pipes.

lstat() and S_ISFIFO are provided by libroken, so do not need to be hidden
behind conditional compilation.

Change-Id: I828534be69949fe017cc7dbed1b6798aa4c0ba17
Reviewed-on: http://gerrit.openafs.org/11686
Reviewed-by: Perry Ruiter <pruiter@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>