autotest: Deprecate create_hosts(connectivity_class) argument

BUG=chromium:878497
TEST=None

Change-Id: I833a02c4c5596e9bdfe82986ac2b6a22d6b2e9cb
Reviewed-on: https://chromium-review.googlesource.com/1194435
Commit-Ready: Prathmesh Prabhu <pprabhu@chromium.org>
Tested-by: Prathmesh Prabhu <pprabhu@chromium.org>
Reviewed-by: Allen Li <ayatane@chromium.org>
diff --git a/server/hosts/factory.py b/server/hosts/factory.py
index f31fc2c..3c610d9 100644
--- a/server/hosts/factory.py
+++ b/server/hosts/factory.py
@@ -7,6 +7,7 @@
 
 from autotest_lib.client.bin import local_host
 from autotest_lib.client.bin import utils
+from autotest_lib.client.common_lib import deprecation
 from autotest_lib.client.common_lib import error
 from autotest_lib.client.common_lib import global_config
 from autotest_lib.server import utils as server_utils
@@ -152,14 +153,19 @@
                     from the autoserv runtime or the AFE.
     @param host_class: Host class to use, if None, will attempt to detect
                        the correct class.
-    @param connectivity_class: Connectivity class to use, if None will decide
-                               based off of hostname and config settings.
+    @param connectivity_class: DEPRECATED. Connectivity class is determined
+                               internally.
     @param args: Args that will be passed to the constructor of
                  the new host class.
 
     @returns: A host object which is an instance of the newly created
               host class.
     """
+    # Argument deprecated
+    if connectivity_class is not None:
+        deprecation.warn('server.create_hosts:connectivity_class')
+        connectivity_class = None
+
     detected_args = _get_host_arguments(machine)
     hostname = detected_args.pop('hostname')
     afe_host = detected_args['afe_host']
@@ -173,8 +179,7 @@
             host_os = label[len(full_os_prefix):]
             break
 
-    if not connectivity_class:
-        connectivity_class = _choose_connectivity_class(hostname, args['port'])
+    connectivity_class = _choose_connectivity_class(hostname, args['port'])
     # TODO(kevcheng): get rid of the host detection using host attributes.
     host_class = (host_class
                   or OS_HOST_DICT.get(afe_host.attributes.get('os_type'))
diff --git a/server/hosts/factory_unittest.py b/server/hosts/factory_unittest.py
index 38bbcc4..983f93e 100755
--- a/server/hosts/factory_unittest.py
+++ b/server/hosts/factory_unittest.py
@@ -97,15 +97,13 @@
 
 
     def test_use_specified(self):
-        """Confirm that the specified host and connectivity classes are used."""
+        """Confirm that the specified host class is used."""
         machine = _gen_machine_dict()
         host_obj = factory.create_host(
                 machine,
                 _gen_mock_host('specified'),
-                _gen_mock_conn('specified')
         )
         self.assertEqual(host_obj._host_cls_name, 'specified')
-        self.assertEqual(host_obj._conn_cls_name, 'specified')
 
 
     def test_detect_host_by_os_label(self):