detect/iponly: carry on dotted netmask

For calculating the address space to be matched against, the CIDR
netmask is taken to account by the IP Only Engine. However, this netmask
was not set properly for dotted netmasks. Fix it.

Ticket: 9166

src/detect-engine-iponly.c

@@ -294,6 +294,7 @@ static int IPOnlyCIDRItemParseSingle(IPOnlyCIDRItem **pdd, const char *str)
                     goto error;
 
                 dd->netmask = (uint8_t)cidr;
+                netmask = CIDRGet(cidr);
             }
 
             r = inet_pton(AF_INET, ip, &in);