Add ability to configure dnsmasq_dns_servers for dhcp agent

Change-Id: I3731dc4271eac527a83a3beaef713550299ad3b5
Related-Prod: PROD-32949
diff --git a/tests/pillar/gateway_linuxbridge.sls b/tests/pillar/gateway_linuxbridge.sls
index 4cbac35..c3064fd 100644
--- a/tests/pillar/gateway_linuxbridge.sls
+++ b/tests/pillar/gateway_linuxbridge.sls
@@ -28,5 +28,6 @@
     agents:
       dhcp:
         interface_driver: linuxbridge
+        dnsmasq_dns_servers: "8.8.8.8,1.1.1.1"
       l3:
         interface_driver: linuxbridge