net: Rename qemu_del_vlan_client() to qemu_del_net_client()

Another step in moving the vlan feature out of net core.  Users only
deal with NetClientState and therefore qemu_del_vlan_client() should be
named qemu_del_net_client().

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
diff --git a/net/slirp.c b/net/slirp.c
index 1bdad37..9d5ca79 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -275,7 +275,7 @@
     return 0;
 
 error:
-    qemu_del_vlan_client(nc);
+    qemu_del_net_client(nc);
     return -1;
 }