mkdirs.sh copies rather than symlinks license file from
the MASTERINSTANCE on the machine. (In this context,
MASTERINSTANCE is the instance from which the license
file is copied; there is no other connection to the
other instance than the one-time copy of the license
file from it).
This also fixes a bug where the license symlink (now
replaced with a copied license file) had root ownership,
preventing start of the new instance. This would occur
only if all of the following were true:
* mkdirs.sh is being used to create an instance after
the first one on a given machine.
* The mkdirs.cfg or mkdirs.N.cfg specified a value for
MASTERINSTANCE that differs from the new instance.
* mkdirs.sh was run as root.
The workaround was 'sudo chown -h perforce: /p4/N/root/license',
though this is no longer needed with this change.