aoe: remove do-nothing NAME="%k" term from example udev rules

When the example udev rules in the documentation are used without
modification, warnings like the one shown below appear in the system logs:

/var/log/messages:Aug 22 11:09:11 kung udevd[445]: NAME="%k" \
is superfluous and breaks kernel supplied names, please remove \
it from /etc/udev/rules.d/60-aoe.rules:26

Removing the term does not cause any problems with the creation of the
special character and block device nodes.

Signed-off-by: Ed Cashin <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

Documentation/aoe/udev.txt

···
 SUBSYSTEM=="aoe", KERNEL=="flush",	NAME="etherd/%k", GROUP="disk", MODE="0220"
 
 # aoe block devices     
-KERNEL=="etherd*",       NAME="%k", GROUP="disk"
+KERNEL=="etherd*",       GROUP="disk"