Update okhttp to 2.1.0.
Update okhttp to 2.1.0.

- https://github.com/UweTrottmann/SeriesGuideInternal/issues/202
- https://github.com/square/okhttp/blob/master/CHANGELOG.md#version-210

0359xiaodong/SeriesGuide,epiphany27/SeriesGuide,UweTrottmann/SeriesGuide,r00t-user/SeriesGuide,artemnikitin/SeriesGuide,hoanganhx86/SeriesGuide,UweTrottmann/SeriesGuide