Added CN=$DD and changed all $DD/p4/common entries to $CN/p4/common in
order to allow you to install an instance on a different depotdata
volume than the 1st instance. Before this change, doing that would
incorrectly create a common folder on the 2nd depotdata volume.
Also removed the lines that copy the binaries from an existing
/p4/common/bin folder back to the SDP. It is perfectly acceptable
to install another instance that is using a newer version than
the existing instance.