mds: fix not journaling client metadata

Previously the code was there for storing in
the SessionMap table, but not for the ESession
logevent.

Fixes: #9518

Signed-off-by: John Spray <john.spray@redhat.com>
Merge pull request #2515 from ceph/wip-9518

mds: fix not journaling client metadata

Reviewed-by: Yan, Zheng <ukernel@gmail.com>