gssd: have gssd deal with scopeid field in upcall

gssd: have gssd deal with scopeid field in upcall

Recent kernels (2.6.32) have started displaying the scopeid for some
addresses in the upcall. gssd doesn't know how to deal with them. Change
gssd to use getaddrinfo instead of inet_pton since that can deal with
scopeid's in addresses. That also allows us to elminate the port
conversion in read_service_info.

If getaddrinfo returns an address with a non-zero sin6_scope_id however,
reject it. getnameinfo ignores that field and just uses the sin6_addr
part when resolving. But, two addresses that differ only in
sin6_scope_id could refer to completely different hosts.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve Dickson <steved@redhat.com>