f examples/firmware_swapping: fix whitespaces
f examples/firmware_swapping: fix whitespaces

jbeyerstedt/RIOT-OTA-update,jbeyerstedt/RIOT-OTA-update,jbeyerstedt/RIOT-OTA-update,jbeyerstedt/RIOT-OTA-update,jbeyerstedt/RIOT-OTA-update