Check that completion file exists

src/freedombone-selector

 
 function app_is_installed {
 	app_name="$1"
+	if [ ! -f $COMPLETION_FILE ]; then
+		echo "0"
+	fi
+
 	if ! grep -Fxq "install_${app_name}" $COMPLETION_FILE; then
 		echo "0"
 	else