Wait for memberof task and DS to start before proceeding in installation.
This was causing a replica DS instance to crash if the task was not
completed when we attempted a shutdown to do a restart.
In replication.py we were restarting the DS instance without waiting
for the ports to become available.
It is unlikely that the dn of the memberof task will change but just in
case I noted it in the two places it is referenced.
ticket 1188