receiptomatic-www: Kill all children upon SIGTERM
receiptomatic-www: Kill all children upon SIGTERM

When the master process receives a SIGTERM, have it kill all its
child processes.

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

ac000/receiptomatic