receiver: Change a while {...} loop to do {...} while
receiver: Change a while {...} loop to do {...} while

Do this in main(), it's a little cleaner and we no longer
need to initialise bytes_read

Signed-off-by: Andrew Clayton <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@opentechlabs.co.uk>

ac000/receiptomatic