qa/cephfs: fix test_evict_client

explictly kill stale session, otherwise session count check is racy.

Fixes: https://tracker.ceph.com/issues/40173
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>

qa/tasks/cephfs/test_misc.py

@@ -122,13 +122,16 @@ def test_evict_client(self):
         ls_data = self.fs.mds_asok(['session', 'ls'])
         self.assert_session_count(1, ls_data)
 
+        mount_a_client_id = self.mount_a.get_global_id()
         self.mount_a.kill()
         self.mount_a.kill_cleanup()
 
         time.sleep(session_autoclose * 1.5)
         ls_data = self.fs.mds_asok(['session', 'ls'])
         self.assert_session_count(1, ls_data)
 
+        self.fs.mds_asok(['session', 'evict', "%s" % mount_a_client_id])
+
         self.mount_a.mount()
         self.mount_a.wait_until_mounted()
         self.mount_b.mount()