CLOUDSTACK-1670: Fix multiple nic routing issue when dhcp_release available

dnsmasq.conf need to contain /etc/dhcpopts.txt from the beginning, otherwise
SIGHUP won't make dnsmasq reload the dhcpopts.txt, thus result in multiple nics
user VM get router information from all DHCP offers.

patches/systemvm/debian/config/etc/dnsmasq.conf.tmpl

@@ -632,3 +632,5 @@ log-facility=/var/log/dnsmasq.log
 # Include a another lot of configuration options.
 #conf-file=/etc/dnsmasq.more.conf
 conf-dir=/etc/dnsmasq.d
+
+dhcp-optsfile=/etc/dhcpopts.txt

patches/systemvm/debian/config/etc/init.d/cloud-early-config

@@ -634,6 +634,9 @@ setup_common() {
 
 setup_dnsmasq() {
   log_it "Setting up dnsmasq"
+
+  touch /etc/dhcpopts.txt
+
   [ -z $DHCP_RANGE ] && [ $ETH0_IP ] && DHCP_RANGE=$ETH0_IP
   [ $ETH0_IP6 ] && DHCP_RANGE_IP6=$ETH0_IP6
   [ -z $DOMAIN ] && DOMAIN="cloudnine.internal"