Fix the build worker api link

<blockquote class="twitter-tweet" lang="en"><p><a href="https://twitter.com/kimsk">@kimsk</a> it should be <a href="http://t.co/MIGbvKiSrp">http://t.co/MIGbvKiSrp</a> - will fix that shortly.</p>&mdash; AppVeyor CI (@appveyor) <a href="https://twitter.com/appveyor/status/542423598657310721">December 9, 2014</a></blockquote>
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