avoid repeat vhost existance checks when adding vhosts

Author: Ayanda-D

deps/rabbit/src/rabbit_vhost.erl

@@ -336,7 +336,7 @@ put_vhost(Name, Description, Tags0, DefaultQueueType, Trace, Username) ->
                                         Metadata0#{default_queue_type =>
                                                        DefaultQueueType}
                                 end,
-                     case add(Name, Metadata, Username) of
+                     case catch do_add(Name, Metadata, Username) of
                          ok ->
                              %% wait for up to 45 seconds for the vhost to initialise
                              %% on all nodes

deps/rabbitmq_event_exchange/src/rabbit_exchange_type_event.erl

@@ -107,10 +107,7 @@ code_change(_OldVsn, State, _Extra) -> {ok, State}.
 %%----------------------------------------------------------------------------
 
 ensure_vhost_exists(VHost) ->
-    case rabbit_vhost:exists(VHost) of
-        false -> rabbit_vhost:add(VHost, ?INTERNAL_USER);
-        _     -> ok
-    end.
+    rabbit_vhost:add(VHost, ?INTERNAL_USER).
 
 %% pattern matching is way more efficient that the string operations,
 %% let's use all the keys we're aware of to speed up the handler.