Calico: fix node ip subnet detection (#7065)

We are currently setting the IP variable to hostIP,
Before https://github.com/projectcalico/node/pull/593

 (not yet released)
Calico interpret that as hostIP/32
Using 'can-reach' we get the future behavior
This fixes vxlan and IPIP CrossSubnet modes

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>