Make ipv6 prefix-length unsigned
Make ipv6 prefix-length unsigned

Addressing:
oval_ip_address.c:82:3: warning: pointer targets in passing argument 2 of 'ipv6addr_parse' differ in signedness [-Wpointer-sign]
   ipv6addr_parse(oval_ip_string, mask_out, ip_out);
   ^
oval_ip_address.c:75:12: note: expected 'int *' but argument is of type 'uint32_t *'
 static int ipv6addr_parse(const char *oval_ipv6_string, int *len_out, struct in6_addr *ip_out);

redhatrises/openscap,openprivacy/openscap,openprivacy/openscap,OpenSCAP/openscap,mpreisler/openscap,mpreisler/openscap,isimluk/openscap,isimluk/openscap,Hexadorsimal/openscap,jan-cerny/openscap,isimluk/openscap,postfix/openscap,openprivacy/openscap,ybznek/openscap,ybznek/openscap,OpenSCAP/openscap,redhatrises/openscap,mpreisler/openscap,mpreisler/openscap,openprivacy/openscap,postfix/openscap,mpreisler/openscap,jan-cerny/openscap,postfix/openscap,OpenSCAP/openscap,isimluk/openscap,ybznek/openscap,ybznek/openscap,mpreisler/openscap,openprivacy/openscap,OpenSCAP/openscap,postfix/openscap,Hexadorsimal/openscap,redhatrises/openscap,Hexadorsimal/openscap,postfix/openscap,isimluk/openscap,jan-cerny/openscap,OpenSCAP/openscap,jan-cerny/openscap,postfix/openscap,ybznek/openscap,jan-cerny/openscap,isimluk/openscap,ybznek/openscap,openprivacy/openscap,Hexadorsimal/openscap,jan-cerny/openscap,Hexadorsimal/openscap,Hexadorsimal/openscap,redhatrises/openscap,redhatrises/openscap,redhatrises/openscap,OpenSCAP/openscap