app: remove unused variable
app: remove unused variable

Reported-by: herbetom <46f1a0bd5592a2f9244ca321b129902a06b53e03@herbetom.de>

codedust/gluon-firmware-wizard,freifunk-darmstadt/gluon-firmware-wizard,freifunk-darmstadt/gluon-firmware-wizard,codedust/gluon-firmware-wizard,freifunk-darmstadt/gluon-firmware-wizard,codedust/gluon-firmware-wizard