Test the riak_core repo's feature/change_net_ticktime branch.

Curious reviewers may be interested in un-commenting
some of the code in `confirm/0` to try another two
attempts to change the tick time.  Yes, it should work.  :-)
From review: don't hardcode backend in the test
Disable siblings, fix sleep time fat-finger
Rename riak_core_util -> riak_core_net_ticktime
Review: convert poll loop -> rt:wait_until()
More review feedback
Merge pull request #408 from basho/slf-tick-change

Test the riak_core repo's feature/change_net_ticktime branch.