Refined '-f' (fast) mode in mkdirs.sh.
As before, we skip the
big 'chown -R' commands in fast mode. But with this change, we
do targeted 'chown' commands to ensure key directories like
/hxdepots/p4/N and /hxdepots/p4/N/depots and
/hxcheckpionts/p4/N/checkpoints have correct ownership.