Due to an error in driving GitLab, this commit erroneously contained the
entirety of !267 (zpos support in the KMS backend) squashed into one
single commit, pushed into master.
In order to keep the history clean, this is being reverted; a rebased
version of !267 with the clear individual commits which were already
present will be applied in its place.
This reverts commit 95e3b0deae85a9c5b96097da843ce3c254cfcee1.
2cb926c558