Hey, it may never happen, that one wants to distinguish attributes by
trailing spaces, but we should not lose the control over it, just for
being lazy :)
Here we remove the trailing spaces of the sysfs attribute only if the
configured value to match doesn't have any trailing spaces by itself.
So if you put a attribute in a rule with spaces at the end, the sysfs
attribute _must_ match exactly.
Is that cool for everyone?
As usual, 2 tests are added for it with a artificial sysfs file and
a few words to the man page.
