build (travis): fix build after travis update (#505)
build (travis): fix build after travis update (#505)


dhlab-basel/Knora,musicEnfanthen/Knora,dhlab-basel/Knora,dhlab-basel/Knora,dhlab-basel/Knora,dhlab-basel/Knora,nie-ine/Knora,nie-ine/Knora,dhlab-basel/Knora,musicEnfanthen/Knora,nie-ine/Knora,musicEnfanthen/Knora,dhlab-basel/Knora,musicEnfanthen/Knora,musicEnfanthen/Knora,musicEnfanthen/Knora,musicEnfanthen/Knora,nie-ine/Knora,nie-ine/Knora,nie-ine/Knora