Fix for issue 2407: dsreplication enable : can't configure several instances when using the same "source".
The problem was that the code (if the skip port check was not present) did check that the provided replication port was available in the *local* host.  If it was not the case, the error message appeared.  The fix consists of performing this check only if the user specified to configure the local server (the only host on which we can actually perform the check).

The workaround for this issue is to use the skipPortCheck argument.