rpc:call try/catch rex

```
/Users/joe/dev/basho/riak_ee/deps/riak_pipe/src/riak_pipe.erl:
  429        || Node <- riak_core_node_watcher:nodes(riak_pipe) ];
  430  active_pipelines(Node) when is_atom(Node) ->
  431:     case rpc:call(Node, riak_pipe_builder_sup, pipelines, []) of
  432          {badrpc, _}=Reason ->
  433              {error, Reason};
  ...
  531              %% lookup vnode pid
  532              Node = riak_core_ring:index_owner(Ring, Partition),
  533:             {ok, Vnode} = rpc:call(Node,
  534                                     riak_core_vnode_master, get_vnode_pid,
  535                                     [Partition, riak_pipe_vnode]),

/Users/joe/dev/basho/riak_ee/deps/riak_pipe/src/riak_pipe_vnode.erl:
  370              %% monitor new vnode, since the input will be handled
  371              %% there, instead of at the vnode originally contacted
  372:             {ok, NextPid} = rpc:call(Next,
  373                                       riak_core_vnode_master,
  374                                       get_vnode_pid,
```