rabbitmq-run.mk: Stop node in start-background-broker in case of error

[Why]
The CLI sometimes crashes early because it fails to configure the Erlang
distribution.

Because we use two CLI commands to watch the start of RabbitMQ, if one
of them fails, the Make recipe will exit with an error, leaving the
RabbitMQ node running.

[How]
We use a shell trap to stop the node if the shell is about to exit with
an error.

While here, we retry the `await_startup` CLI command several times
because this is the one failing the most. This is until the crash is
understood and a proper fix is committed.

Author: dumbbell

deps/rabbit_common/mk/rabbitmq-run.mk

@@ -323,10 +323,13 @@ start-background-broker: node-tmpdir $(DIST_TARGET)
 	$(BASIC_SCRIPT_ENV_SETTINGS) \
 	  $(RABBITMQ_SERVER) \
 	  $(REDIRECT_STDIO) &
+	trap 'test "$$?" = 0 || $(MAKE) stop-node' EXIT && \
 	ERL_LIBS="$(DIST_ERL_LIBS)" \
 	  $(RABBITMQCTL) -n $(RABBITMQ_NODENAME) wait --timeout $(RMQCTL_WAIT_TIMEOUT) $(RABBITMQ_PID_FILE) && \
-	ERL_LIBS="$(DIST_ERL_LIBS)" \
-	  $(RABBITMQCTL) --node $(RABBITMQ_NODENAME) await_startup
+	for i in $$(seq 1 10); do \
+	  ERL_LIBS="$(DIST_ERL_LIBS)" $(RABBITMQCTL) -n $(RABBITMQ_NODENAME) await_startup || sleep 1; \
+	done && \
+	ERL_LIBS="$(DIST_ERL_LIBS)" $(RABBITMQCTL) -n $(RABBITMQ_NODENAME) await_startup
 
 start-rabbit-on-node:
 	$(exec_verbose) ERL_LIBS="$(DIST_ERL_LIBS)" \