fix build script (#1600)
fix build script (#1600)


DuncanmaMSFT/docfx,superyyrrzz/docfx,dotnet/docfx,928PJY/docfx,pascalberger/docfx,928PJY/docfx,pascalberger/docfx,dotnet/docfx,DuncanmaMSFT/docfx,dotnet/docfx,hellosnow/docfx,pascalberger/docfx,hellosnow/docfx,928PJY/docfx,superyyrrzz/docfx,hellosnow/docfx,superyyrrzz/docfx