Revert "cp11-migrate: Integration with LibFormat"

This reverts commit r186866.

This breaks the build and the original author Guillaume Papin
<guillaume.papin@epitech.eu> asked me to revert so he could look at it more with
revane.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@186873 91177308-0d34-0410-b5e6-96231b3b80d8