Move dnsmasq-neutron.conf to /etc/neutron/dnsmasq

The default dnsmasq configuration file doesn't operate with the Kilo
agents in /etc/neutron when used with the --config-dir option.  Instead move
it to a subdirectory.

Change-Id: Iab8a54e879f8e630ba38205750ca9670e82834df
Partially-Implements: blueprint port-kilo

docker/neutron/neutron-agents/config-scripts/config-dhcp-agent.sh

@@ -8,9 +8,11 @@ set -e
 : ${DHCP_DRIVER:=neutron.agent.linux.dhcp.Dnsmasq}
 : ${USE_NAMESPACES:=true}
 : ${DELETE_NAMESPACES:=true}
-: ${DNSMASQ_CONFIG_FILE:=/etc/neutron/dnsmasq-neutron.conf}
+: ${DNSMASQ_CONFIG_FILE:=/etc/neutron/dnsmasq/dnsmasq-neutron.conf}
 : ${ROOT_HELPER:=sudo neutron-rootwrap /etc/neutron/rootwrap.conf}
 
+mkdir -p $(dirname $DNSMASQ_CONFIG_FILE)
+
 check_required_vars VERBOSE_LOGGING DEBUG_LOGGING MECHANISM_DRIVERS \
                     DHCP_DRIVER USE_NAMESPACES DELETE_NAMESPACES \
                     NEUTRON_LOG_DIR DNSMASQ_CONFIG_FILE \