[PATCH] Bugfix in template instantiation.

[Richard Smith]

This is the wrong fix. The bug is that `TreeTransform::RebuildCXXPseudoDestructorExpr` is building a bogus `CXXScopeSpec` here:

    // The scope type is now known to be a valid nested name specifier
    // component. Tack it on to the end of the nested name specifier.
    if (ScopeType)
      SS.Extend(SemaRef.Context, SourceLocation(),
                ScopeType->getTypeLoc(), CCLoc);

If `ScopeType` is not a class type, we should reject it at this point.

http://reviews.llvm.org/D5769