ns_memcached and ns_janitor waiting for "default" to shut down for too long (> 8 mins)

In automation tests we tend to create and delete buckets very often.

while deleting and recreating the default buckets it takes memcached more than 10 mins to accept any set/get command.

I can see lot of "waiting" messages in the log starting from 09:03 to 9:10

ns_1@127.0.0.1:<0.1507.0>:ns_memcached:443: Waiting for "default" to finish shutting down before we start it.

In order to reproduce you can run expirytests

dataops/expiry/expiry-small-keys