Travis: deal with new build environments
Travis: deal with new build environments

The latest Travis updates seem to only install the requested Python.
Previously, we assumed we had all Pythons even when the requested Python was
the default.

untitaker/beets,jcoady9/beets,dfc/beets,Andypsamp/CODjunit,Kraymer/beets,SusannaMaria/beets,Andypsamp/CODfinalJUNIT,gabrielaraujof/beets,xsteadfastx/beets,mathstuf/beets,shanemikel/beets,ttsda/beets,sadatay/beets,shanemikel/beets,lightwang1/beets,Andypsamp/CODjunit,kelvinhammond/beets,xsteadfastx/beets,mried/beets,ruippeixotog/beets,SusannaMaria/beets,beetbox/beets,Wen777/beets,artemutin/beets,andremiller/beets,shamangeorge/beets,MyTunesFreeMusic/privacy-policy,xsteadfastx/beets,jackwilsdon/beets,ibmibmibm/beets,jackwilsdon/beets,jmwatte/beets,Andypsamp/CODfinalJUNIT,diego-plan9/beets,swt30/beets,untitaker/beets,drm00/beets,PierreRust/beets,bj-yinyan/beets,parapente/beets,Andypsamp/CODfinalJUNIT,kareemallen/beets,imsparsh/beets,multikatt/beets,YetAnotherNerd/beets,drm00/beets,mathstuf/beets,dfc/beets,Freso/beets,ttsda/beets,LordSputnik/beets,madmouser1/beets,mried/beets,randybias/beets,parapente/beets,dfc/beets,asteven/beets,dfc/beets,shanemikel/beets,ttsda/beets,kareemallen/beets,mathstuf/beets,sampsyo/beets,xsteadfastx/beets,Freso/beets,moodboom/beets,sampsyo/beets,ibmibmibm/beets,drm00/beets,Wen777/beets,MyTunesFreeMusic/privacy-policy,YetAnotherNerd/beets,pkess/beets,gabrielaraujof/beets,swt30/beets,randybias/beets,YetAnotherNerd/beets,swt30/beets,tima/beets,bj-yinyan/beets,artemutin/beets,arabenjamin/beets,marcuskrahl/beets,Andypsamp/CODjunit,mosesfistos1/beetbox,Dishwishy/beets,imsparsh/beets,marcuskrahl/beets,Dishwishy/beets,ibmibmibm/beets,multikatt/beets,kareemallen/beets,sampsyo/beets,jackwilsdon/beets,ruippeixotog/beets,asteven/beets,artemutin/beets,Dishwishy/beets,jmwatte/beets,kareemallen/beets,diego-plan9/beets,jcoady9/beets,arabenjamin/beets,pkess/beets,SusannaMaria/beets,mried/beets,marcuskrahl/beets,randybias/beets,Freso/beets,arabenjamin/beets,imsparsh/beets,mosesfistos1/beetbox,asteven/beets,mosesfistos1/beetbox,asteven/beets,gabrielaraujof/beets,bj-yinyan/beets,mried/beets,sadatay/beets,multikatt/beets,imsparsh/beets,madmouser1/beets,lengtche/beets,moodboom/beets,untitaker/beets,sadatay/beets,PierreRust/beets,beetbox/beets,kelvinhammond/beets,swt30/beets,arabenjamin/beets,diego-plan9/beets,sadatay/beets,PierreRust/beets,Dishwishy/beets,madmouser1/beets,shamangeorge/beets,beetbox/beets,shamangeorge/beets,Andypsamp/CODfinalJUNIT,lengtche/beets,m-urban/beets,marcuskrahl/beets,lightwang1/beets,SusannaMaria/beets,Freso/beets,lengtche/beets,beetbox/beets,jcoady9/beets,LordSputnik/beets,ruippeixotog/beets,gabrielaraujof/beets,tima/beets,jmwatte/beets,YetAnotherNerd/beets,untitaker/beets,diego-plan9/beets,Kraymer/beets,andremiller/beets,mathstuf/beets,kelvinhammond/beets,drm00/beets,m-urban/beets,Kraymer/beets,PierreRust/beets,jcoady9/beets,jackwilsdon/beets,Andypsamp/CODjunit,ruippeixotog/beets,moodboom/beets,Andypsamp/CODfinalJUNIT,parapente/beets,ibmibmibm/beets,mosesfistos1/beetbox,lightwang1/beets,jmwatte/beets,pkess/beets,MyTunesFreeMusic/privacy-policy,lengtche/beets,moodboom/beets,tima/beets,m-urban/beets,kelvinhammond/beets,sampsyo/beets,Wen777/beets,ttsda/beets,madmouser1/beets,andremiller/beets,lightwang1/beets,LordSputnik/beets,m-urban/beets,multikatt/beets,Kraymer/beets,artemutin/beets,Andypsamp/CODjunit,LordSputnik/beets,tima/beets,shamangeorge/beets,bj-yinyan/beets,randybias/beets,parapente/beets,shanemikel/beets,pkess/beets,MyTunesFreeMusic/privacy-policy