bonding: IFF_BONDING is not stripped on enslave failure

While enslaving a new device and after IFF_BONDING flag is set, in case
of failure it is not stripped from the device's priv_flags while
cleaning up, which could lead to other problems.
Cleaning at err_close because the flag is set after dev_open().

v2: no change

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -1906,6 +1906,7 @@ err_detach:
 	write_unlock_bh(&bond->lock);
 
 err_close:
+	slave_dev->priv_flags &= ~IFF_BONDING;
 	dev_close(slave_dev);
 
 err_unset_master: