www/audit: Fix a potential issue in match_ipv4()
www/audit: Fix a potential issue in match_ipv4()

Now that we compile with -Wextra, I was getting the following compiler
warning

  CC	audit.o
In file included from audit.c:23:
audit.c: In function ‘match_ipv4’:
audit.c:82:34: warning: left shift of negative value [-Wshift-negative-value]
   82 |  n_addr = addr.s_addr & htonl(~0 << (32 - cidr));
      |                                  ^~

We need to make the ~0, ~0UL

Signed-off-by: Andrew Clayton <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@digital-domain.net>

ac000/receiptomatic