CIFS: Respect epoch value from create lease context v2

that force a client to purge cache pages when a server requests it.

Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>

diff --cc fs/cifs/cifsfs.c
Simple merge

diff --cc fs/cifs/cifsglob.h
Simple merge

diff --cc fs/cifs/file.c
Simple merge

diff --cc fs/cifs/smb2misc.c
Simple merge

diff --cc fs/cifs/smb2ops.c
Simple merge

diff --cc fs/cifs/smb2pdu.c
Simple merge