Changing to fetching the list of peers first, then check if the riak_kv
service is up. If the service is up, then check the peers. Otherwise it
is possible to see the service down, then peers up because it went up in
the interim.
Also, making KV vnode delay configurable.
Now ensemble peers are prevented from starting up until the riak_kv
service is up to avoid nasty races that could even lead to node crashes
as the ensembles frantically query for data that isn't ready.
Add ensemble_basic, ensemble_basic2, and ensemble_basic3 tests.
These tests test that Riak correctly generates proper consensus
groups, these groups reach quorum, handle leader failures, etc.
ensemble_basic3 tests basic consistent K/V API as well as behavior
during simple network partitions.
