tests: Fix route_scale startup issues

tests: Fix route_scale startup issues

Upstream CI is frequently running into a situation where
the routes are not being installed.  These routes
start at the beginning and suddenly in the middle
they start working properly.

D   1.0.15.183/32 [150/0] via 192.168.0.1, r1-eth0 inactive, weight 1, 00:10:17
                          via 192.168.1.1, r1-eth1 inactive, weight 1, 00:10:17
D   1.0.15.184/32 [150/0] via 192.168.0.1, r1-eth0 inactive, weight 1, 00:10:17
                          via 192.168.1.1, r1-eth1 inactive, weight 1, 00:10:17
D   1.0.15.185/32 [150/0] via 192.168.0.1, r1-eth0 inactive, weight 1, 00:10:17
                          via 192.168.1.1, r1-eth1 inactive, weight 1, 00:10:17
D>* 1.0.15.186/32 [150/0] via 192.168.0.1, r1-eth0, weight 1, 00:10:17
  *                       via 192.168.1.1, r1-eth1, weight 1, 00:10:17
D>* 1.0.15.187/32 [150/0] via 192.168.0.1, r1-eth0, weight 1, 00:10:17
  *                       via 192.168.1.1, r1-eth1, weight 1, 00:10:17
D>* 1.0.15.188/32 [150/0] via 192.168.0.1, r1-eth0, weight 1, 00:10:17

Turning on some debugs showed that the failed installed routes are
trying to be matched against the default route.  Thus implying
all the connected routes for the test are not yet successfully
installed.  Let's modify the test(s) on startup to just ensure
that the connected routes are installed correctly.  I am no
longer seeing the problem after this change.

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