Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/appveyor.bat

Index: third_party/protobuf/appveyor.bat
diff --git a/third_party/protobuf/appveyor.bat b/third_party/protobuf/appveyor.bat
deleted file mode 100644
index 356a13f86bf5b20534810c4a574cefd3f6125131..0000000000000000000000000000000000000000
--- a/third_party/protobuf/appveyor.bat
+++ /dev/null
@@ -1,29 +0,0 @@
-setlocal
-
-IF %language%==cpp GOTO build_cpp
-IF %language%==csharp GOTO build_csharp
-
-echo Unsupported language %language%. Exiting.
-goto :error
-
-:build_cpp
-echo Building C++
-mkdir build_msvc
-cd build_msvc
-cmake -G "%generator%" -DBUILD_SHARED_LIBS=%BUILD_DLL% ../cmake
-msbuild protobuf.sln /p:Platform=%vcplatform% /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll" || goto error
-cd %configuration%
-tests.exe || goto error
-goto :EOF
-
-:build_csharp
-echo Building C#
-cd csharp\src
-nuget restore
-msbuild Google.Protobuf.sln /p:Platform="Any CPU" /logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll" || goto error
-nunit-console Google.Protobuf.Test\bin\%configuration%\Google.Protobuf.Test.dll || goto error
-goto :EOF
-
-:error
-echo Failed!
-EXIT /b %ERRORLEVEL%