zero-length ranges: valid on windows, but nfs servers MUST return NFS4ERR_INVAL for LOCK with length=0. use MRxIsLockRealizable() to return STATUS_NOT_SUPPORTED for zero-length ranges (avoiding the lock upcall and rpc)
ranges that extend past UINT64_MAX: not valid on windows. NFS expects length=UINT64_MAX for locking to end-of-file. use length=UINT64_MAX if length >= UINT64_MAX-offset (making lock ranges consistent with linux client)
Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>