New algorithm of searching metadata for disks after provisioning

Try to use "extra" field to match metadata/disk first. It has better chance
to survive OS/kernel change. If it doesn't work, use disk-by-path instead

Related-Bug: 1283790

Change-Id: I48e93e77e7d27ecae23d291e30d5e24009d5a637
Merge "New algorithm of searching metadata for disks after provisioning"