Ensure that dnsmasq is terminated when running unstack.sh

If the Quantum dhcp-agent is enabled then we ensure that the dnsmasq
process is termated when running unstack.sh

Change-Id: I0aee8b806c61dff42400a3b8552b7c748e9c5adf
diff --git a/unstack.sh b/unstack.sh
index 641d34e..6a55a0a 100755
--- a/unstack.sh
+++ b/unstack.sh
@@ -63,3 +63,8 @@
         stop_service mysql
     fi
 fi
+
+# Quantum dhcp agent runs dnsmasq
+if is_service_enabled q-dhcp; then
+    sudo kill -9 $(ps aux | awk '/[d]nsmasq.+interface=tap/ { print $2 }')
+fi