Start the dns resolver process on demand

Change-Id: Iab27b405fb3ca7aed94ae974d57c286c41298c3a
Signed-off-by: Dave Barach <dave@barachs.net>
diff --git a/src/vnet/dns/dns.c b/src/vnet/dns/dns.c
index 2951679..bae6cb4 100644
--- a/src/vnet/dns/dns.c
+++ b/src/vnet/dns/dns.c
@@ -74,6 +74,9 @@
   u32 n_vlib_mains = tm->n_vlib_mains;
   vlib_main_t *vm = dm->vlib_main;
 
+  /* Create the resolver process if not done already */
+  vnet_dns_create_resolver_process (dm);
+
   if (is_enable)
     {
       if (vec_len (dm->ip4_name_servers) == 0