[BOND]: Fix bond_init() error path handling.

From: Florin Malita <fmalita@gmail.com>

bond_init() is not releasing rtnl_sem after register_netdevice() and before
calling unregister_netdevice() (from bond_free_all()) in the exception
path.  As the device registration is not completed (dev->reg_state ==
NETREG_REGISTERING), the call to unregister_netdevice() triggers
BUG_ON(dev->reg_state != NETREG_REGISTERED).

Signed-off-by: Florin Malita <fmalita@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>