Neutron: use "OSC show -f value -c id" instead of "OSC list + grep"

We should leverage server-side filtering.

Change-Id: I3deef791868769b0b7cfc405d73dff57458ca427
diff --git a/tools/ping_neutron.sh b/tools/ping_neutron.sh
index c755754..73fe3f3 100755
--- a/tools/ping_neutron.sh
+++ b/tools/ping_neutron.sh
@@ -54,7 +54,7 @@
 REMAINING_ARGS="${@:2}"
 
 # BUG: with duplicate network names, this fails pretty hard.
-NET_ID=$(openstack network list | grep "$NET_NAME" | awk '{print $2}')
+NET_ID=$(openstack network show -f value -c id "$NET_NAME")
 PROBE_ID=$(neutron-debug probe-list -c id -c network_id | grep "$NET_ID" | awk '{print $2}' | head -n 1)
 
 # This runs a command inside the specific netns