Libvirt:Instance resize confirm issue against NFS

when I test resize-confirm on NFS (KVM) using at least two
compute nodes, OSError will occur when try to cleanup the
backup instance directory and will make instance status
"Error".

One way to cleanup resize is using delay_on_retry and
maximum attempts setting. Replace rmtree() because
execute() have more parameters choices.

Closes-Bug: #1248019

Change-Id: Ifb9a500bbba805af0317307c2e7d6903dcd02ad1
(cherry picked from commit 17d131661740e452e9729d9ac8881e6fede23dd7)
Fixes the Hyper-V agent individual disk metrics

Replaces aggregated metric values with separated values for each disk.

(cherry picked from commit a41ef0ede2cdace1db4d932e0931509a84ba837e)

Change-Id: I3c264dfd52572e5c429ee606a47a5727a4a3af3c
Closes-Bug: #1290403
Merge "Libvirt:Instance resize confirm issue against NFS" into stable/havana