Critical Description
When RpcRetryingCaller.callWithRetries() attempts a retry, it calls RetryingCallable.prepare(tries != 0). For RegionServerCallable (and probably others), this will wind up calling RegionLocator.getRegionLocation(reload=true), which will drop the meta cache for the given region and always go back to meta.
This is kind of silly, since in the case of exceptions, we already call RetryingCallable.throwable(), which goes to great pains to only refresh the meta cache when necessary. Since we are already doing this on failure, I don't really understand why we are doing duplicate work to refresh the meta cache on prepare() at all.