Major Description
Related to: MB-21574
Our customers are going to attempt to use XDCR to replicate from <4.6 clusters into >= 4.6 clusters and so we need to be prepared for that.
Two issues at hand:
1 - Given that we will not support non-LWW buckets being used in an XDCR stream with LWW buckets, we should do our best in the product to prevent that from happening. Either a warning or an actual prevention would be appropriate. Instead of the "CAS drift" message, I could see us showing an alert that says "looks like you're trying to do something we don't support" so that the user can self-remedy
2 - We will have to continue to support non-LWW buckets on both ends of the stream between <4.6 and >=4.6. Given that we are still tracking the CAS drift exceptions even for non-LWW buckets, we should ensure that there are no unforeseen consequences of leaving XDCR running for a long time and potentially receiving an infinite number of these exceptions in the stats, buffers, etc.
