Fix af_packet issues:

1. Fix af_packet memory leak;
2. Fix close socket twice;
3. Adjust debug log for syscall;
4. Adjust dhcp client output log;

Change-Id: I96bfaef16c4fad80c5da0d9ac602f911fee1670d
Signed-off-by: jackiechen1985 <xiaobo.chen@tieto.com>
diff --git a/src/vnet/dhcp/client.c b/src/vnet/dhcp/client.c
index 1d53521..b89b8f2 100644
--- a/src/vnet/dhcp/client.c
+++ b/src/vnet/dhcp/client.c
@@ -830,13 +830,14 @@
 
   if (c->leased_address.as_u32)
     {
-      s = format (s, "addr %U/%d gw %U\n",
+      s = format (s, "addr %U/%d gw %U",
 		  format_ip4_address, &c->leased_address,
 		  c->subnet_mask_width, format_ip4_address,
 		  &c->router_address);
 
       vec_foreach (addr, c->domain_server_address)
-	s = format (s, "dns %U ", format_ip4_address, addr);
+	s = format (s, " dns %U", format_ip4_address, addr);
+      vec_add1 (s, '\n');
     }
   else
     {