builder/docker: remove the exit code file when we're done
builder/docker: remove the exit code file when we're done

Kaixiang/packer,suma/packer,Kaixiang/packer,TranscendComputing/packer,suma/packer,TranscendComputing/packer,TranscendComputing/packer,suma/packer,Kaixiang/packer,suma/packer,Kaixiang/packer,TranscendComputing/packer