(FACT-234) Add blockdevice uuid fact

Add facts to show the uuid of partitions.

Looks for the partition of block devices found in /sys/block/<device>/<device>*
Then looks for the a link to the partition device in /dev/disk/by-uuid.  The link name is the UUID.

JIRA: FACT-234
(maint) Remove trailing spaces in blockdevices_spec
Merge branch 'feature/facter-2/patition_uuid_fact' into facter-2

* feature/facter-2/patition_uuid_fact:
  (maint) Remove trailing spaces in blockdevices_spec
  (FACT-234) Add blockdevice uuid fact