Add ability to configure dnsmasq_dns_servers for dhcp agent

Change-Id: I3731dc4271eac527a83a3beaef713550299ad3b5
Related-Prod: PROD-32949
diff --git a/neutron/files/pike/dhcp_agent.ini b/neutron/files/pike/dhcp_agent.ini
index 907677b..b4bfda0 100644
--- a/neutron/files/pike/dhcp_agent.ini
+++ b/neutron/files/pike/dhcp_agent.ini
@@ -113,7 +113,9 @@
 
 # Comma-separated list of the DNS servers which will be used as forwarders. (list value)
 # Deprecated group/name - [DEFAULT]/dnsmasq_dns_server
-#dnsmasq_dns_servers = <None>
+{%- if neutron.get('agents', {}).get('dhcp', {}).dnsmasq_dns_servers is defined %}
+dnsmasq_dns_servers = {{ neutron.agents.dhcp.dnsmasq_dns_servers }}
+{%- endif %}
 
 # Base log dir for dnsmasq logging. The log contains DHCP and DNS log information and is useful for debugging issues with either DHCP or
 # DNS. If this section is null, disable dnsmasq log. (string value)
diff --git a/neutron/files/queens/dhcp_agent.ini b/neutron/files/queens/dhcp_agent.ini
index dab89ad..bc270c8 100644
--- a/neutron/files/queens/dhcp_agent.ini
+++ b/neutron/files/queens/dhcp_agent.ini
@@ -112,6 +112,9 @@
 # Comma-separated list of the DNS servers which will be used as forwarders.
 # (list value)
 #dnsmasq_dns_servers =
+{%- if neutron.get('agents', {}).get('dhcp', {}).dnsmasq_dns_servers is defined %}
+dnsmasq_dns_servers = {{ neutron.agents.dhcp.dnsmasq_dns_servers }}
+{%- endif %}
 
 # Base log dir for dnsmasq logging. The log contains DHCP and DNS log
 # information and is useful for debugging issues with either DHCP or DNS. If
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