HAMMER VFS - Fix edge case in mirroring code.

HAMMER VFS - Fix edge case in mirroring code.

There is an edge case where a record is physically destroyed on the master
and a mirroring or mirror-streaming operation attempts to delete the record
on the slave using a mirror-end TID that in fact matches the create_tid of
the record.  This results in a protective panic.

Fix the problem simply by not deleting such edge-case records.  They will
be deleted in the next pass, since in order to have been destroyed on the
master the master must have done the operation with a larger TID then
the create_tid of the record that was destroyed.

Reported-by: Brad Frank <brad.frank@gmail.com>