Remove bad status check in isSuccess

[bearfriend]

See #58

The return statement that I modified seems like it shouldn't be necessary to be any more complicated than the one step that I left. The !status was causing any status equal to 0 to return true.

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[bearfriend]

Signed!

[googlebot]

CLAs look good, thanks!

[addyosmani]

Change LGTM - we're dropping that !0 issue that was evaluating to true. cc @garlicnation in case this needs to be backed out.

[garlicnation]

Thanks addy!