The generic networking code ensures that no two networking devices
have the same name, so  there is no time except when sysfs has
implementation bugs that device_rename when called from
dev_change_name will fail.

The current error handling for errors from device_rename in
dev_change_name is wrong and results in an unusable and unrecoverable
network device if device_rename is happens to return an error.

This patch removes the buggy error handling.  Which confines the mess
when device_rename hits a problem to sysfs, instead of propagating it
the rest of the network stack.  Making linux a little more robust.

Without this patch you can observe what happens when sysfs has a bug
when CONFIG_SYSFS_DEPRECATED is not set and you attempt to rename
a real network device to a name like (broken_parity_status, device,
modalias, power, resource2, subsystem_vendor, class,  driver, irq,
msi_bus, resource, subsystem, uevent, config, enable, local_cpus,
numa_node, resource0, subsystem_device, vendor)

Greg has a patch that fixes the sysfs bugs but he doesn't trust it
for a 2.6.21 timeframe.  This patch which just ignores errors should
be safe and it keeps the system from going completely wacky.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>