bozo: Fix the test for bosserver '-cores none'

bozo: Fix the test for bosserver '-cores none'

The check for the '-cores none' parameter is incorrect resulting in the
parameter to be taken as a directory path.

Update the string comparison.

Change-Id: I0d72c1add52d36e40f75981a86c16b5689d38fd8
Reviewed-on: https://gerrit.openafs.org/14559
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>