receiver: Use bool instead of int in receiptomatic.c
receiver: Use bool instead of int in receiptomatic.c

Seeing as we are using C99, in send_error_email(), switch the
sent_email variable from an int to a bool.

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

ac000/receiptomatic