ipvs: Don't protect ip_vs_addr_is_unicast with CONFIG_SYSCTL

I arranged the code so that the compiler can remove the unecessary bits
in ip_vs_leave when CONFIG_SYSCTL is unset, and removed an explicit
CONFIG_SYSCTL.

Unfortunately when rebasing my work on top of that of Alex Gartrell I
missed the fact that the newly added function ip_vs_addr_is_unicast was
surrounded by CONFIG_SYSCTL.

So remove the now unnecessary CONFIG_SYSCTL guards around
ip_vs_addr_is_unicast.  It is causing build failures today when
CONFIG_SYSCTL is not selected and any self respecting compiler will
notice that sysctl_cache_bypass is always false without CONFIG_SYSCTL
and not include the logic from the function ip_vs_addr_is_unicast in
the compiled code.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>