Let net_tap_set_fd() do only fd-related setup.

Actually, for further backend-transfer migration for virtio-net/tap
we'll want to skip net_tap_set_fd() (as incoming fds are already
prepared by source QEMU). So move tap_read_poll() to net_tap_setup().

Don't care about using_vnet_hdr and vhost_net, the state is
zero-initialized.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
 net/tap.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/tap.c b/net/tap.c
index dbd1eb3a17..340d8d0cda 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -467,7 +467,6 @@ static bool net_tap_set_fd(TAPState *s, int fd, int vnet_hdr, Error **errp)
 {
     s->fd = fd;
     s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
-    s->using_vnet_hdr = false;
     s->has_ufo = tap_probe_has_ufo(s->fd);
     s->has_uso = tap_probe_has_uso(s->fd);
     s->enabled = true;
@@ -479,8 +478,6 @@ static bool net_tap_set_fd(TAPState *s, int fd, int vnet_hdr, Error **errp)
     if (vnet_hdr) {
         tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
     }
-    tap_read_poll(s, true);
-    s->vhost_net = NULL;
 
     if (s->sndbuf) {
         Error **e = s->sndbuf_required ? errp : NULL;
@@ -781,6 +778,8 @@ static bool net_tap_setup(TAPState *s, int fd, int vnet_hdr, Error **errp)
         return false;
     }
 
+    tap_read_poll(s, true);
+
     if (s->vhostfd != -1) {
         VhostNetOptions options;
 
-- 
2.48.1