Merging r196852:

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r196852 | majnemer | 2013-12-09 16:40:58 -0800 (Mon, 09 Dec 2013) | 10 lines

Sema: Enforce C++11 pointer-to-member template arguments should rules

The standard is pretty clear on what it allows inside of template
arguments for non-type template parameters of pointer-to-member.

They must be of the form &qualified-id and cannot come from sources like
constexpr VarDecls or things of that nature.

This fixes PR18192.

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llvm-svn: 196885