flaky test fix: t/expirations.t
flaky test fix: t/expirations.t

Not really fixing this; need some infrastructure to halt then force the
clock to specific times. Cranking the times should reduce the
flakiness; if it doesn't we'll set them to SKIP:

dormando/memcached,dormando/memcached,memcached/memcached,memcached/memcached,memcached/memcached,memcached/memcached,dormando/memcached,dormando/memcached,memcached/memcached,dormando/memcached