Temporarily revert to picasso 2.2.0.
Temporarily revert to picasso 2.2.0.

- Not updating until https://github.com/square/picasso/pull/557 (alpha fix) has shipped.

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