qa/tasks: drop test_cephadm_orchestrator.py

this test will end with a failure like

```
2020-01-30T18:15:15.870 INFO:tasks.ceph.mgr.x.smithi042.stderr:Warning: Permanently added 'smithi042.front.sepia.ceph.com,172.21.15.42' (ECDSA) to the list of known hosts.
2020-01-30T18:15:15.925 INFO:tasks.ceph.mgr.x.smithi042.stderr:Permission denied, please try again.
2020-01-30T18:15:15.932 INFO:tasks.ceph.mgr.x.smithi042.stderr:Permission denied, please try again.
2020-01-30T18:15:15.939 INFO:tasks.ceph.mgr.x.smithi042.stderr:root@smithi042.front.sepia.ceph.com: Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
```

because mgr is not able to establish an ssh connection to that host with "root".
please note, the teuthology worker is acting using the "ubuntu" account on the
test node, and by default, "root" does not have its pubkey. and actually
`qa/tasks/cephadm.py` does push the pubkey to all the managed hosts before
testing cephadm.

since `qa/tasks/cephadm.py` is a better test for cephadm, let's just
drop this one.

as suites/rados/cephadm already covers cephadm

Signed-off-by: Kefu Chai <kchai@redhat.com>

qa/suites/rados/singleton-flat/cephadm_orchestrator/.qa

@@ -1 +0,0 @@
-../.qa

qa/suites/rados/singleton-flat/cephadm_orchestrator/2-node-mgr.yaml

@@ -1 +0,0 @@
-.qa/clusters/2-node-mgr.yaml

qa/suites/rados/singleton-flat/cephadm_orchestrator/centos_latest.yaml

@@ -1 +0,0 @@
-.qa/distros/supported/centos_latest.yaml

qa/suites/rados/singleton-flat/cephadm_orchestrator/cephadm_orchestrator.yaml

@@ -1,18 +0,0 @@
-
-tasks:
-  - install:
-  - ceph:
-      # tests may leave mgrs broken, so don't try and call into them
-      # to invoke e.g. pg dump during teardown.
-      wait-for-scrub: false
-      log-whitelist:
-        - overall HEALTH_
-        - \(MGR_DOWN\)
-        - \(MGR_INSIGHTS_WARNING\)
-        - \(insights_health_check
-        - \(PG_
-        - replacing it with standby
-        - No standby daemons available
-  - cephfs_test_runner:
-      modules:
-        - tasks.mgr.test_cephadm_orchestrator

qa/suites/rados/singleton-flat/cephadm_orchestrator/mgr.yaml

@@ -1 +0,0 @@
-.qa/debug/mgr.yaml

qa/tasks/mgr/test_cephadm_orchestrator.py

@@ -1,23 +0,0 @@
-import logging
-from mgr_test_case import MgrTestCase
-
-log = logging.getLogger(__name__)
-
-class TestOrchestratorCli(MgrTestCase):
-    MGRS_REQUIRED = 1
-
-    def _orch_cmd(self, *args):
-        return self.mgr_cluster.mon_manager.raw_cluster_cmd("orchestrator", *args)
-
-    def setUp(self):
-        super(TestOrchestratorCli, self).setUp()
-        self._load_module("orchestrator_cli")
-        self._load_module("cephadm")
-        self._orch_cmd("set", "backend", "cephadm")
-
-    def test_host_ls(self):
-        self._orch_cmd("host", "add", "osd0")
-        self._orch_cmd("host", "add", "mon0")
-        ret = self._orch_cmd("host", "ls")
-        self.assertIn("osd0", ret)
-        self.assertIn("mon0", ret)