Fix = delete in MSVC build from r211705

MSVC doesn't support = delete yet, use LLVM_DELETED_FUNCTION instead.

Related to: http://reviews.llvm.org/D3390

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211709 91177308-0d34-0410-b5e6-96231b3b80d8