allow to pass options to dnsmasq service

There were request to pass parameters to dnsmasq container in kube-dns
addon.

This PR adds variable master.addons.dns.dnsmasq (dict) which can be
used to pass options to dnsmasq container. Defaults are configured in
metadata.

Change-Id: If072e31a8a1cde4c984c67373ad74d45204619b0
diff --git a/metadata/service/master/cluster.yml b/metadata/service/master/cluster.yml
index 46d391f..62e1042 100644
--- a/metadata/service/master/cluster.yml
+++ b/metadata/service/master/cluster.yml
@@ -32,6 +32,11 @@
           replicas: 1
           domain: cluster.local
           server: 10.254.0.10
+          dnsmasq:
+            cache-size: 1000
+            no-resolv:
+            server: 127.0.0.1#10053
+            log-facility: "-"
         dashboard:
           enabled: True
         heapster_influxdb: