Fixes to replication2 for 2.0: allow_mult=false for mutator; rhc fix

Get the test passing with 2 small fixes after these crashes:


Mutator:
================ replication2 failure stack trace =====================
{{badmatch,[{{dict,5,16,16,8,80,48,
                   {[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]},
                   {{[],[],[],[],
                     [[cluster_of_record,65],
                      [mutators_applied,riak_repl_reduced]],
                     [],[],[],[],[],
                     [[<<"X-Riak-VTag">>,49,56,48,120,83,112,53,109,69,74,74,
                       48,81,108,99,103,112,115,82,74,86,70]],
                     [[<<"index">>]],
                     [],
                     [[<<"X-Riak-Last-Modified">>|{1384,471557,44502}]],
                     [],[]}}},
             <<0,0,3,132>>},
            {{dict,5,16,16,8,80,48,
                   {[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]},
                   {{[],[],[],[],
                     [[cluster_of_record,65],
                      [mutators_applied,riak_repl_reduced]],
                     [],[],[],[],[],
                     [[<<"X-Riak-VTag">>,49,77,106,107,69,52,66,83,102,73,83,
                       80,116,87,68,57,104,82,75,69,74,57]],
                     [[<<"index">>]],
                     [],
                     [[<<"X-Riak-Last-Modified">>|{1384,471562,248058}]],
                     [],[]}}},
             <<0,0,3,132>>}]},
 [{riak_object,get_value,1,[{file,"src/riak_object.erl"},{line,355}]},
  {rt,'-systest_read/5-fun-0-',5,[{file,"src/rt.erl"},{line,942}]},
  {lists,foldl,3,[{file,"lists.erl"},{line,1197}]}


And rhc:
---------------------------------------------------------------------------------------------------------------------------------------------
19:15:13.196 [warning] replication2 failed: {function_clause,[{rhc,create,["127.0.0.1",{"127.0.0.1",10058},"riak",[]],[{file,"src/rhc.erl"},{line,84}]},{replication2,http_write_during_shutdown,3,[{file,"tests/replication2.erl"},{line,550}]},{replication2,replication,3,[{file,"tests/replication2.erl"},{line,460}]},{replication2,confirm,0,[{file,"tests/replication2.erl"},{line,52}]}]}
19:15:13.196 [error] Error in process <0.127.0> on node 'riak_test@127.0.0.1' with exit value: {function_clause,[{rhc,create,["127.0.0.1",{"127.0.0.1",10058},"riak",[]],[{file,"src/rhc.erl"},{line,<wbr>84}]},{replication2,http_write_during_shutdown,3,[{file,"tests/replication2.erl"},{line,550}]},{replication2,replication,3,[{file,"t...