Create empty config file if none found (see #467)
Create empty config file if none found (see #467)

We already had code in place for this, but it was run after the config
validation, so on a new installation Mopidy would fail because of missing
config values before the config file was created.

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