ceph: optimize mds session register

Do memory allocation first, so that avoid unnecessary
initialization of newly allocated session in error case.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
1 file changed