Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/python/google/protobuf/pyext/descriptor.h

Index: third_party/protobuf/python/google/protobuf/pyext/descriptor.h
diff --git a/third_party/protobuf/python/google/protobuf/pyext/descriptor.h b/third_party/protobuf/python/google/protobuf/pyext/descriptor.h
index 1ae0e672ed37a7e007885832ba5071f429aa2cdb..eb99df182e79a403eda1d9880dde12ea3cc2e54d 100644
--- a/third_party/protobuf/python/google/protobuf/pyext/descriptor.h
+++ b/third_party/protobuf/python/google/protobuf/pyext/descriptor.h
@@ -47,8 +47,6 @@ extern PyTypeObject PyEnumDescriptor_Type;
 extern PyTypeObject PyEnumValueDescriptor_Type;
 extern PyTypeObject PyFileDescriptor_Type;
 extern PyTypeObject PyOneofDescriptor_Type;
-extern PyTypeObject PyServiceDescriptor_Type;
-extern PyTypeObject PyMethodDescriptor_Type;
 
 // Wraps a Descriptor in a Python object.
 // The C++ pointer is usually borrowed from the global DescriptorPool.
@@ -62,10 +60,6 @@ PyObject* PyEnumValueDescriptor_FromDescriptor(
 PyObject* PyOneofDescriptor_FromDescriptor(const OneofDescriptor* descriptor);
 PyObject* PyFileDescriptor_FromDescriptor(
     const FileDescriptor* file_descriptor);
-PyObject* PyServiceDescriptor_FromDescriptor(
-    const ServiceDescriptor* descriptor);
-PyObject* PyMethodDescriptor_FromDescriptor(
-    const MethodDescriptor* descriptor);
 
 // Alternate constructor of PyFileDescriptor, used when we already have a
 // serialized FileDescriptorProto that can be cached.