ksmbd: set v2 lease version on lease upgrade

If file opened with v2 lease is upgraded with v1 lease, smb server
should response v2 lease create context to client.
This patch fix smb2.lease.v2_epoch2 test failure.

This test case assumes the following scenario:
 1. smb2 create with v2 lease(R, LEASE1 key)
 2. smb server return smb2 create response with v2 lease context(R,
LEASE1 key, epoch + 1)
 3. smb2 create with v1 lease(RH, LEASE1 key)
 4. smb server return smb2 create response with v2 lease context(RH,
LEASE1 key, epoch + 2)

i.e. If same client(same lease key) try to open a file that is being
opened with v2 lease with v1 lease, smb server should return v2 lease.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Acked-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Steve French <stfrench@microsoft.com>