Removed unrecognized option from no_package.proto

python/google/protobuf/internal/no_package.proto

 syntax = "proto2";
 
-option py_api_version = 2;
-
 enum NoPackageEnum {
   NO_PACKAGE_VALUE_0 = 0;
   NO_PACKAGE_VALUE_1 = 1;
@@ -9,4 +7,4 @@ enum NoPackageEnum {
 
 message NoPackageMessage {
   optional NoPackageEnum no_package_enum = 1;
-}
\ No newline at end of file
+}