Fix the manpage to describe the real behaviour of $attr: It doesn't search all
parent devices any more, just the one selected by KERNELS etc.
https://launchpad.net/bugs/348513
<listitem>
<para>The value of a sysfs attribute found at the device, where
all keys of the rule have matched. If the matching device does not have
- such an attribute, follow the chain of parent devices and use the value
- of the first attribute that matches.
+ such an attribute, and a previous KERNELS, SUBSYSTEMS, DRIVERS, or
+ ATTRS test selected a parent device, use the attribute from that
+ parent device.
If the attribute is a symlink, the last element of the symlink target is
returned as the value.</para>
</listitem>