When setting up agreements we need to be careful in not allowing to
'reconnect' a master that was previously completely deleted as it would
misses entries that are vital for proper functioning. This change in code
fixes 2 problems with the current approach.
1) it removes false positives when we are tryig to reconnect a replica that
was previosuly merely disconnected but was still part of the domain and just
replicating via a different topology and not a direct link
2) adds checks for entries that are deleted when an actual removal is
performed. so that we cannot 'reconnect' previously unrelated replicas when
one of the 2 has been permanently deleted from the masters tree.
Second part of ticket https://fedorahosted.org/freeipa/ticket/2925
Simo Sorce
32c1aa45b3