We have an API for setting the admin password for an already created
instance and we have a metadata API for retrieving the encrypted
password. In the libvirt driver, when a request to set the admin
password is received, it is indeed set in the guest but the instance
system metadata is never updated with the encrypted password, so
attempts to retrieve the password via the metadata service API result
in an empty string returned instead of the encrypted password.
This has been broken in the libvirt driver since the set admin password
password feature was added, as far as I can tell. The xen api driver,
however, handles the same thing correctly and this adds similar logic
to the libvirt driver to fix the problem.
Closes-Bug: #1748544
Change-Id: Icf44c4c94529cb75232abe1f3ecc5a4d3646b0cc
715a3cadb0