libudev: list - properly sort linked list not only the index

libudev: list - properly sort linked list not only the index

<mgorny> it seems that udev-git is b0rked while tag '173' works fine for me
<mgorny> the rule in question is:
<mgorny> also, with >173 persistent-net rules seem to get constantly recreated
         for same devices
<kay> mgorny: logic bug. we only sort the keys in an index, but we don't care
      about the index when reading the list, which doesn't work too well for
      the rules file list where we depend on the order