This issue is exercised by the smbtorture4 SMB2-LOCK-MULTIPLE-LOCK test.
When an unlock and lock request are given, in that order, in a SMB_LOCK request
the unlock should succeed, followed by the lock failing with INVALID_PARAMETER.
This behavior is documented in MS-SMB2 188.8.131.52.1
samba4.smb2.lock.*.MULTIPLE-UNLOCK should be removed from
source4/selftest/knownfail when this bug is fixed.
Reassign file server related bugs up to tridge.