Revert "Warning for framework headers using double quote includes"

This reverts commit 9b5ff2db7e31c4bb11a7d468260b068b41c7c285.

Broke bots:

http://lab.llvm.org:8011/builders/clang-x64-ninja-win7/builds/11315
http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win/builds/10411/steps/test-check-all/logs/stdio

llvm-svn: 335195