virtio: fix coverity warnings

Fix 3 coverity warnings
1. api_format.c: init net_ns = 0 and remove its corresponding vec_add and
vec_free
2. netlink.c (reported in tap.c before the code was removed): resource leaked
due to fd is not close
3. tap.c: subtract 1 for size when calling strncpy to accommodate the
terminated NULL character

Change-Id: Iff4e66604862f0c06dac227b8cfd48d3979e41a5
Signed-off-by: Steven <sluong@cisco.com>
diff --git a/src/vnet/devices/netlink.c b/src/vnet/devices/netlink.c
index b2a6513..b05daf2 100644
--- a/src/vnet/devices/netlink.c
+++ b/src/vnet/devices/netlink.c
@@ -48,16 +48,16 @@
 
   memset (&req, 0, sizeof (req));
   if ((sock = socket (AF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) == -1)
-    {
-      err = clib_error_return_unix (0, "socket(AF_NETLINK)");
-      goto error;
-    }
+    return clib_error_return_unix (0, "socket(AF_NETLINK)");
 
   ra.nl_family = AF_NETLINK;
   ra.nl_pid = getpid ();
 
   if ((bind (sock, (struct sockaddr *) &ra, sizeof (ra))) == -1)
-    return clib_error_return_unix (0, "bind");
+    {
+      err = clib_error_return_unix (0, "bind");
+      goto error;
+    }
 
   req.nh.nlmsg_len = NLMSG_LENGTH (sizeof (struct ifinfomsg));
   req.nh.nlmsg_flags = NLM_F_REQUEST;
@@ -75,6 +75,7 @@
     err = clib_error_return_unix (0, "send");
 
 error:
+  close (sock);
   return err;
 }
 
diff --git a/src/vnet/devices/virtio/tap.c b/src/vnet/devices/virtio/tap.c
index f6db2c9..34339c9 100644
--- a/src/vnet/devices/virtio/tap.c
+++ b/src/vnet/devices/virtio/tap.c
@@ -109,7 +109,7 @@
     }
 
   ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR;
-  strncpy (ifr.ifr_ifrn.ifrn_name, (char *) args->name, IF_NAMESIZE);
+  strncpy (ifr.ifr_ifrn.ifrn_name, (char *) args->name, IF_NAMESIZE - 1);
   _IOCTL (vif->tap_fd, TUNSETIFF, (void *) &ifr);
 
   vif->ifindex = if_nametoindex ((char *) args->name);