Change some smart_ptr == 0 to smart_ptr == nullptr.  Fixes http://llvm.org/bugs/show_bug.cgi?id=12185.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@152240 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed