minimal reproduction of #417

write a single object to node A (with indexing setup), install
intercept to make yz_solr:cores/0 slow on node B and join B to node A.
wait until riak_test times out waiting for no pending changes (there
will always be one, because of the written object)
Merge pull request #418 from basho/bug/jrw/indefinite-handoff-blocking

minimal reproduction of #417

Reviewed-by: coderoshi