k20: Don't build app_empty as it's currently broken
k20: Don't build app_empty as it's currently broken

gapry/zinc,ryankurte/zinc,ntwyman/zinc,farcaller/zinc,phil-opp/zinc,troplin/zinc,dirvine/zinc,phil-opp/zinc,hackndev/zinc,0xc0170/zinc,farcaller/zinc,hackndev/zinc,aethaniel/zinc,dirvine/zinc,phil-opp/zinc,ryankurte/zinc,ryankurte/zinc,placrosse/zinc,flxo/zinc,richo/zinc,posborne/zinc,troplin/zinc,hackndev/zinc,aethaniel/zinc,mcoffin/zinc,posborne/zinc,ntwyman/zinc,posborne/zinc,farcaller/zinc,ntwyman/zinc,mcoffin/zinc,richo/zinc,tempbottle/zinc,mcoffin/zinc,phil-opp/zinc,dirvine/zinc,farcaller/zinc,placrosse/zinc,gapry/zinc,flxo/zinc,troplin/zinc,posborne/zinc,darayus/zinc,posborne/zinc,placrosse/zinc,hackndev/zinc,tempbottle/zinc,richo/zinc,0xc0170/zinc,ryankurte/zinc,troplin/zinc,hackndev/zinc,placrosse/zinc,ntwyman/zinc,hugwijst/zinc,ryankurte/zinc,placrosse/zinc,mcoffin/zinc,tempbottle/zinc,hugwijst/zinc,tempbottle/zinc,phil-opp/zinc,troplin/zinc,dirvine/zinc,farcaller/zinc,dirvine/zinc,ntwyman/zinc,richo/zinc,mcoffin/zinc,darayus/zinc,tempbottle/zinc,richo/zinc