qa: add a check for crash_replay_interval autoset

... that after a fs new on fresh pools, crash_replay_interval
is set to the default on the data pool.

Signed-off-by: John Spray <john.spray@redhat.com>
mon/MDSMonitor: EC check in 'fs new' like newfs

Signed-off-by: John Spray <john.spray@redhat.com>