Disabled litlint. It requires Python 2.7 or later

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@208823 91177308-0d34-0410-b5e6-96231b3b80d8
migrate litlint from argparse to optparse.  reenabled

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@208826 91177308-0d34-0410-b5e6-96231b3b80d8