[PATCH] Fix for libc++ bug #20096 http://llvm.org/bugs/show_bug.cgi?id=20096

[Eric Fiselier]

Indeed, and if you test this change with a deleted destructor it is not destructible. 
However I don't see why a pure virtual destructor is explicitly deleted. Can you clarify on that?

P.S. A deleted destructor test-case should probably be added.

http://reviews.llvm.org/D4306