[PATCH] Don't eagerly evaluate the TypeSourceInfo when mangling names.

[Zachary Turner]

majnemer@ caught up with me offline and suggested a different fix, which is to simply call the getSourceRange() method of VarDecl instead of going through the TypeSourceInfo.  This also solves the problem, so I will commit this fix instead as it seems more straightforward.

http://reviews.llvm.org/D4281