revive dtrace

[llelf]

dtrace -q -n 'erlang*:::user_trace-i4s4
{ printf("%s|%10s %10s  %s\n", cwd, riak_op.bk, riak_op.op, riak_op.stage)  }
' 
devstage1|     A,k-0        get  init
devstage1|     A,k-0        put  init
devstage1|     A,k-0        put  prepare
devstage1|     A,k-0        put  validate
devstage1|     A,k-0        put  precommit
devstage1|     A,k-0        put  execute_local
devstage1|     A,k-0        put  waiting_local_vnode
devstage1|     A,k-0        put  waiting_local_vnode
devstage1|     A,k-0        put  execute_remote
devstage1|     A,k-0        put  waiting_remote_vnode
devstage1|     A,k-0        put  waiting_remote_vnode
devstage1|     A,k-0        put  waiting_remote_vnode
devstage1|     A,k-0        put  process_reply
devstage1|     A,k-0        put  postcommit
devstage1|     A,k-0        put  finish

riak_kv changes coming soon

[llelf]

/cc @mrallen1 @slfritchie