Default task failover policy enhancements

The new failover policy enhancements behave differently than the 5.1 release. The default is a random failover, which causes problems in my environment due to pessimistic locks being acquired. The default policy should be "none"

Secondly, if a user specifies a key set, the failover policy should respect that. Using pessimistic locks as an example, a valid optimization would be to submit on the local data owner to avoid additional RPCs. A random node failover policy really doesn't fit in this case.