Revert "Bazel rules for gRPC Python interop tests"

This reverts commit 9172775.

Author: mehrdada

requirements.bazel.txt

@@ -8,4 +8,3 @@ wheel>=0.29
 futures>=2.2.0
 google-auth>=1.0.0
 oauth2client==4.1.0
-requests>=2.14.2

src/proto/grpc/testing/BUILD

@@ -64,15 +64,6 @@ grpc_proto_library(
     has_services = False,
 )
 
-py_proto_library(
-    name = "py_messages_proto",
-    protos = ["messages.proto",],
-    with_grpc = True,
-    deps = [
-        requirement('protobuf'),
-    ],
-)
-
 grpc_proto_library(
     name = "metrics_proto",
     srcs = ["metrics.proto"],
@@ -125,17 +116,3 @@ grpc_proto_library(
         "messages_proto",
     ],
 )
-
-py_proto_library(
-    name = "py_test_proto",
-    protos = ["test.proto",],
-    with_grpc = True,
-    deps = [
-        requirement('protobuf'),
-    ],
-    proto_deps = [
-        ":py_empty_proto",
-        ":py_messages_proto",
-    ]
-)
-