USHRT_MAX is not good enough because the value is 65535 which specifies
the number of bits in bitmap.  The allowed port range is 0-65535 so we
need to increase the number.

We could have USHRT_MAX + 1 but let's define the number explicitly.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1590214Reviewed-by: NJán Tomko <jtomko@redhat.com>
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>