[PATCH] NVTPX: Use MapMetadata() instead of incorrect, custom logic

[Duncan P. N. Exon Smith]

r225943 and r225944.  Thanks for the review!

> On 2015 Jan 13, at 18:20, Justin Holewinski <justin.holewinski at gmail.com> wrote:
> 
> This looks reasonable to me.  Thanks for updating this!
> 
> On Tue, Jan 13, 2015 at 5:44 PM, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
> NVTPX has its own `remapMDNode()` which (1) does strange things and
> (2) is bitrotting.
> 
> The first patch removes the strange, invalid logic to replace a
> global variable declaration (see the actual
> `DIBuilder::createGlobalVariable()` for what the field *really*
> does -- ignore the comment) with a ConstantInt representing the
> address space.  (It'll mangle any other metadata schema that
> happens to reference global variables, as well.)
> 
> The second patch rewrites the logic to use `MapMetadata()`, so that
> this code doesn't continue to bitrot.
> 
> These aren't really NFC, but it doesn't cause any test failures.
>