VS2017 Fix

[dilevin]

This is a fix for Issue #263 - "Compilation error in "newest" VIsual Studio"

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This change is 

[sherm1]

I don't have the right version of VS2017 to check this but the fix looks right and makes sense to me. I verified that the CI failures are just the previously reported Mac problems and are unrelated. I think it is safe to merge this -- @SeanCurtis-TRI do you agree?

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Reviewed 1 of 1 files at r1.
Review status: all files reviewed at latest revision, all discussions resolved, some commit checks failed.

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Comments from Reviewable

[SeanCurtis-TRI]

If we want to stall the weekend, I can probably test it myself. It's a shame that CI can't confirm it, but that's life. So, if we feel strongly about testing corroboration, I'll try it Monday. If we don't feel strongly, go ahead and merge (and I'll probably try it Monday anyways.)

[sherm1]

Seems better to merge it now -- I'll do that.

[sherm1]

Thanks, @dilevin !