Whitelist files and block devices instead of blacklisting fifos and
character devices.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175549 91177308-0d34-0410-b5e6-96231b3b80d8
Fix a bug that was found by the clang static analyzer. The var "AT" is null so we cant deref it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175550 91177308-0d34-0410-b5e6-96231b3b80d8