www: url_handlers: Simplify setting of 'join' in approve_receipts()
www: url_handlers: Simplify setting of 'join' in approve_receipts()

In approve_receipts() we set a variable 'join' to either contain ' OR '
or be empty. Before we were using strcpy() to set this. Instead declare
this variable as a const char * and just set it directly.

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

ac000/receiptomatic