The Python interop client.

The server_host_override flag's implementation remaining
outstanding means that this only works over insecure
connections for now.
diff --git a/src/python/interop/setup.py b/src/python/interop/setup.py
index 4b7709f..6db5435 100644
--- a/src/python/interop/setup.py
+++ b/src/python/interop/setup.py
@@ -40,7 +40,9 @@
 }
 
 _PACKAGE_DATA = {
-    'interop': ['credentials/server1.key', 'credentials/server1.pem',]
+    'interop': [
+        'credentials/ca.pem', 'credentials/server1.key',
+        'credentials/server1.pem',]
 }
 
 _INSTALL_REQUIRES = ['grpc-2015>=0.0.1']