Remove py_api_version proto option to fix build failure.

davidzchen · davidzchen · commit cef789c0b067 · 2016-05-06T07:53:19.000Z
--
MOS_MIGRATED_REVID=121654048
diff --git a/skydoc/build.proto b/skydoc/build.proto
@@ -16,7 +16,6 @@ syntax = "proto2";
 
 package skydoc;
 
-option py_api_version = 2;
 
 message Attribute {
   // Indicates the type of attribute.
