Handle error in first call for mfg data

@jh-bate -- this handles the case where the device didn't respond

cool- already merged :)

On Thu, Dec 11, 2014 at 4:01 PM, Kent Quirk <notifications@github.com>
wrote:

> In lib/dexcomDriver.js
> <https://github.com/tidepool-org/chrome-uploader/pull/30#discussion-diff-21655603>
> :
>
> > @@ -413,6 +413,9 @@ module.exports = function (config) {
> >      // var cmd = readEGVDataPages(
>
> I will -- but not as part of this PR, please.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/tidepool-org/chrome-uploader/pull/30/files#r21655603>.
>