tests: Set mask to a default value for addKernelRoute

tests: Set mask to a default value for addKernelRoute

When looking for a implied host route it is not necessary
to add the `/32` to an ip route add.  As such masks
will not be set in this case.  Set the value of masks
to a known good value so that when the route installation
fails the test for it actually being there will tell you
that the route is not there -vs- complaining about mask
being uninited.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>