ceph: convert comma to semicolon in __ceph_dentry_dir_lease_touch()

Replace a comma between expression statements by a semicolon.

Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>