check-rabbitmq-queue: Use list_queues output for current backlog size.
check-rabbitmq-queue: Use list_queues output for current backlog size.

The value in the stats file can get outdated if the queue hasn't done
enough iterations to update the stats file for a while. The queue size
output by rabbitmqctl list_queues is more up to date, and empirically
tends to agree with the value in the stats file (when the stats file is
fresh).

punchagan/zulip,hackerkid/zulip,eeshangarg/zulip,rht/zulip,rht/zulip,showell/zulip,punchagan/zulip,zulip/zulip,showell/zulip,hackerkid/zulip,kou/zulip,hackerkid/zulip,kou/zulip,eeshangarg/zulip,zulip/zulip,eeshangarg/zulip,zulip/zulip,punchagan/zulip,punchagan/zulip,kou/zulip,zulip/zulip,showell/zulip,eeshangarg/zulip,kou/zulip,eeshangarg/zulip,eeshangarg/zulip,andersk/zulip,zulip/zulip,hackerkid/zulip,showell/zulip,kou/zulip,punchagan/zulip,andersk/zulip,showell/zulip,rht/zulip,zulip/zulip,hackerkid/zulip,kou/zulip,hackerkid/zulip,rht/zulip,rht/zulip,rht/zulip,andersk/zulip,andersk/zulip,hackerkid/zulip,kou/zulip,eeshangarg/zulip,showell/zulip,andersk/zulip,showell/zulip,rht/zulip,punchagan/zulip,andersk/zulip,punchagan/zulip,andersk/zulip,zulip/zulip