Recently discovered performance issues with the libgcrypt library [1]
mean that operators may wish to avoid the now default native decryption
of LUKSv1 volumes as of I5a0de814f2868f1a4980a69b72b45ee829cedb94.
This change introduces a ``[workarounds]/disable_native_luksv1``
option to disable this native decryption by QEMU, allowing Nova to
fallback to the dm-crypt based os-brick encryptors.
This workaround is temporary and will be removed during the W release
once all impacted distributions have been able to update their
versions of the libgcrypt library.
The _is_luks_v1 method previously used to confirm if a LUKSv1 encryption
provider is being used has been renamed _allow_native_luksv1 and
repurposed to determine if native LUKSv1 decryption by QEMU is allowed.
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1762765
Closes-Bug: #1869182
Change-Id: Ia500eb614cf575ab846f64f4b69c9068274c8c1f
dbb58e964a