sta: call hva's wait_volumes_available after preparing each volume.
Put a first-boot file on the metadata drive so Windows knows when to generate new passwords
Added a comment explaining why we delete the first-boot file
Use the tmp directory that already exists to mount the metadata drive
Merge pull request #375 from axsh/fix-issue-374

Fix for #374
Revert "mussel: add or_fail_with option to retry functions."

This reverts commit 0b1caf7462ad6251bf72576d56d0fe0da16851ce.
Merge pull request #378 from axsh/revert-retry-sh

Revert "mussel: add or_fail_with option to retry functions."
Merge pull request #376 from axsh/metadata-first-boot-file

Metadata first boot file
Merge branch 'master' into backup-instance-on-shared-vol