clarify error when all_or_nothing attempted

change the error message so that it doesn't imply
that all_or_nothing is a feature that will be
implemented in the future.
diff --git a/src/fabric_doc_update.erl b/src/fabric_doc_update.erl
index 2624c47..10e254f 100644
--- a/src/fabric_doc_update.erl
+++ b/src/fabric_doc_update.erl
@@ -207,7 +207,7 @@
     % TODO actually perform the validation.  This requires some hackery, we need
     % to basically extract the prep_and_validate_updates function from couch_db
     % and only run that, without actually writing in case of a success.
-    Error = {not_implemented, <<"all_or_nothing is not supported yet">>},
+    Error = {not_implemented, <<"all_or_nothing is not supported">>},
     PreCommitFailures = lists:map(fun(#doc{id=Id, revs = {Pos,Revs}}) ->
         case Revs of [] -> RevId = <<>>; [RevId|_] -> ok end,
         {{Id, {Pos, RevId}}, Error}