Always enable route to 172.27.27.0/24

Summary:
A race condition is suspected not to configure the route,
because the tunnel isn't ready and so the gateway IP
not yet reacheable.

This change offers a 30 seconde timer for a new chance
to add the route if not yet configured.

Reviewers: ptdradmin

Reviewed By: ptdradmin

Differential Revision: https://devcentral.nasqueron.org/D3897