Remove warning "find_preferred_connection: no connection and !create"

Remove warning "find_preferred_connection: no connection and !create"

find_preferred_connection() is called with !create via
afs_ConnByHost->afs_ConnBySA to determine if there is a cached
connection available.  Don't warn, as it will next be called with the
create flag to create the connection anyway.

Reviewed-on: https://gerrit.openafs.org/12964
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit 909d8358109445fdb316b68a8e55e17626cf17c9)

Change-Id: If2cb4fd25e98f5bbdde00f76e8b3850c53cb6358
Reviewed-on: https://gerrit.openafs.org/13025
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>