libblkid: cleanup names, don't copy probing results

* cleanup function and variable names (s/vals/values/)
* in "safe probe" mode libblkid copies probing result from the first
  attempt, this is unnecessary, with values list we can just move
  values to another list rather than copy all.
* add new debug messages

Signed-off-by: Karel Zak <kzak@redhat.com>
5 files changed