Use vclock when issuing block deletes
Use vclock when issuing block deletes

Do a head (get w/ [head] option) request to get the
vector clock for a block before issuing the delete.
Use the vclock when issuing the subsequent block
delete.

yangchengjian/riak_cs,GabrielNicolasAvellaneda/riak_cs,basho/riak_cs,dragonfax/riak_cs,basho/riak_cs_lfs,yangchengjian/riak_cs,sdebnath/riak_cs,basho/riak_cs,GabrielNicolasAvellaneda/riak_cs,GabrielNicolasAvellaneda/riak_cs,laurenrother/riak_cs,basho/riak_cs,sdebnath/riak_cs,dragonfax/riak_cs,sdebnath/riak_cs,yangchengjian/riak_cs,GabrielNicolasAvellaneda/riak_cs,yangchengjian/riak_cs,dragonfax/riak_cs,laurenrother/riak_cs,sdebnath/riak_cs,basho/riak_cs_report,laurenrother/riak_cs,basho/riak_cs,laurenrother/riak_cs,dragonfax/riak_cs