libspotify: Fix pylint warnings
libspotify: Fix pylint warnings

pacificIT/mopidy,quartz55/mopidy,bacontext/mopidy,jcass77/mopidy,priestd09/mopidy,mopidy/mopidy,kingosticks/mopidy,hkariti/mopidy,woutervanwijk/mopidy,diandiankan/mopidy,ali/mopidy,bencevans/mopidy,diandiankan/mopidy,jcass77/mopidy,bencevans/mopidy,adamcik/mopidy,tkem/mopidy,mopidy/mopidy,vrs01/mopidy,diandiankan/mopidy,SuperStarPL/mopidy,kingosticks/mopidy,jodal/mopidy,rawdlite/mopidy,glogiotatidis/mopidy,mokieyue/mopidy,vrs01/mopidy,priestd09/mopidy,quartz55/mopidy,pacificIT/mopidy,bencevans/mopidy,swak/mopidy,adamcik/mopidy,tkem/mopidy,SuperStarPL/mopidy,hkariti/mopidy,diandiankan/mopidy,glogiotatidis/mopidy,ZenithDK/mopidy,mokieyue/mopidy,dbrgn/mopidy,jmarsik/mopidy,woutervanwijk/mopidy,mokieyue/mopidy,jmarsik/mopidy,hkariti/mopidy,dbrgn/mopidy,ali/mopidy,rawdlite/mopidy,dbrgn/mopidy,rawdlite/mopidy,priestd09/mopidy,abarisain/mopidy,hkariti/mopidy,jcass77/mopidy,jodal/mopidy,abarisain/mopidy,SuperStarPL/mopidy,ZenithDK/mopidy,jmarsik/mopidy,glogiotatidis/mopidy,ali/mopidy,jmarsik/mopidy,ZenithDK/mopidy,tkem/mopidy,SuperStarPL/mopidy,swak/mopidy,glogiotatidis/mopidy,ali/mopidy,liamw9534/mopidy,mokieyue/mopidy,rawdlite/mopidy,quartz55/mopidy,vrs01/mopidy,liamw9534/mopidy,mopidy/mopidy,swak/mopidy,bencevans/mopidy,bacontext/mopidy,pacificIT/mopidy,adamcik/mopidy,jodal/mopidy,dbrgn/mopidy,bacontext/mopidy,tkem/mopidy,quartz55/mopidy,pacificIT/mopidy,kingosticks/mopidy,bacontext/mopidy,swak/mopidy,vrs01/mopidy,ZenithDK/mopidy