Fix badmatch error that dialyzer found

Pair-programmed with @reiddraper

Previously we were pattern matching a two-tuple where the value returned
was a proplist. This change now treats the value correctly as a
proplist. Note, this is still an issue in 1.4, since this was
forward-ported from the 1.4 series.

src/riak_kv_cinfo.erl

@@ -46,7 +46,9 @@ cluster_info_generator_funs() ->
     ].
 
 aae_throttle(CPid) ->
-    {Throttle, ThrottleLimits} = get_aae_throttle(),
+    Props = get_aae_throttle(),
+    Throttle = proplists:get_value(current_throttle, Props),
+    ThrottleLimits = proplists:get_value(limits, Props),
     cluster_info:format(CPid, "Current throttle: ~p msec\n", [Throttle]),
     cluster_info:format(CPid, "Limit AAE throttle parameters: ~p\n",
                         [ThrottleLimits]).