client: wait rename to finish

client: wait rename to finish

In rare case during the rename if another thread tries to lookup the
dst dentry, it may get an inconsistent result that both src dentry
and dst dentry will link to the same inode at the same time.

Will wait the rename to finish and try it again.

Fixes: https://tracker.ceph.com/issues/49912
Signed-off-by: Xiubo Li <xiubli@redhat.com>
(cherry picked from commit 11fb16df06ad61e228c17feedf00dfb85f0477d5)

Conflicts:
	src/client/Client.h: a minor conflict.