Need to open SED disks after unlocking/Initializing in freebsd

Currently in 11.2 if you remove a a sed encrypted drive and reinsert it 30 seconds later the drive doesn't appear for ZFS even though it is unlocked. Doing false > /dev/da## fixes this.
This needs to be done to trigger geom retasting the disk. Even zpool online doesn't work but once the above command is run

In python open("/dev/da##").close() should work to cover all corner case this should probably be done during after any sed unlock or sed initialize.It's fine if this fails doing to something else beating middleware to exclusive opening the device. This should already be done in some cases.

Will test later with 11.3 once rest of this test cycle is complete and system can be upgraded.