mds: don't rdlock locks in replica object while auth mds is recovering

mds: don't rdlock locks in replica object while auth mds is recovering

Auth mds may take xlock on the lock and change the object when replaying
unsafe requests. To guarantee new requests and replayed unsafe requests
(on auth mds) get processed in proper order, we shouldn't rdlock locks in
replica object while auth mds of the object is recovering

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
(cherry picked from commit 0afbc0338e1b9f32340eaa74899d8d43ac8608fe)