Several changes in udev rules:

Several changes in udev rules:

- add DM_UDEV_RULES_VSN to provide a variable to be checked for in the other
  rules (e.g. to check that DM rules are actually installed, we can alternate
  functionality in the other rules based on this information, also we have
  versioning support for the rules)
- set proper sbin path for dmsetup and blkid, /sbin first, then /usr/sbin.
  This is necessary for anaconda to work properly.
- add 'last_rule' for cryptsetup's temporary devices (symlinks in /dev/mapper
  only)