Khepri: force shrink member to current member

Ra PR pending: rabbitmq/ra#306

Author: dcorbacho

deps/rabbit/src/rabbit_khepri.erl

@@ -86,6 +86,8 @@
 -export([if_has_data/1,
          if_has_data_wildcard/0]).
 
+-export([force_shrink_member_to_current_member/0]).
+
 -ifdef(TEST).
 -export([force_metadata_store/1,
          clear_forced_metadata_store/0]).
@@ -372,6 +374,10 @@ force_reset() ->
     DataDir = maps:get(data_dir, ra_system:fetch(coordination)),
     ok = rabbit_file:recursive_delete(filelib:wildcard(DataDir ++ "/*")).
 
+force_shrink_member_to_current_member() ->
+    ok = ra_server_proc:force_shrink_members_to_current_member(
+           {?RA_CLUSTER_NAME, node()}).
+
 ensure_ra_system_started() ->
     {ok, _} = application:ensure_all_started(khepri),
     ok = rabbit_ra_systems:ensure_ra_system_started(?RA_SYSTEM).