Expand force_client_auth to old ServerCredentials

src/python/grpcio/grpc/_adapter/_intermediary_low.py

@@ -255,6 +255,6 @@ class ClientCredentials(object):
 class ServerCredentials(object):
   """Adapter from old _low.ServerCredentials interface to new _low.ServerCredentials."""
 
-  def __init__(self, root_credentials, pair_sequence):
+  def __init__(self, root_credentials, pair_sequence, force_client_auth):
     self._internal = _low.ServerCredentials.ssl(
-        root_credentials, list(pair_sequence), False)
+        root_credentials, list(pair_sequence), force_client_auth)

src/python/grpcio/grpc/_adapter/fore.py

@@ -288,7 +288,7 @@ class ForeLink(base_interfaces.ForeLink, activated.Activated):
         self._port = self._server.add_http2_addr(address)
       else:
         server_credentials = _low.ServerCredentials(
-          self._root_certificates, self._key_chain_pairs)
+          self._root_certificates, self._key_chain_pairs, False)
         self._server = _low.Server(self._completion_queue)
         self._port = self._server.add_secure_http2_addr(
             address, server_credentials)

src/python/grpcio/grpc/_links/service.py

@@ -366,10 +366,10 @@ class ServiceLink(links.Link):
     """Adds a port on which to service RPCs after this link has been started.
 
     Args:
-      port: The port on which to service RPCs, or zero to request that a port be
-        automatically selected and used.
-      server_credentials: A ServerCredentials object, or None for insecure
-        service.
+      port: The port on which to service RPCs, or zero to request that a port
+        be automatically selected and used.
+      server_credentials: An _intermediary_low.ServerCredentials object, or
+        None for insecure service.
 
     Returns:
       A port on which RPCs will be serviced after this link has been started.