Upgrades to 3.6.1 are broken in OpenShift 4.6

Upgrades to version 3.6.1 are broken in 4.6 clusters. After upgrading the following is logged by the operator:

spec.template.spec.volumes[1].projected: Forbidden: may not specify m
ore than 1 volume type

This problem was introduced by this change. When a Patch operation is executed the actual patch is not executed by the client but it is delegated to the kubernetes API instead.

When adding a "projected" property to a volume that already contains a "secret" entry the latter is not removed, thus generating a volume with both "projected" and "secret" entries (this is invalid, the volume is either a secret/configmap or a projection of multiple secrets/configmaps).

Acceptance criteria

• Upgrades work in 4.6 release
• Upgrades work in 4.7 release
• Test cases exist for upgrades in all supported OpenShift releases (QE Team)

Notes

Working quay instances most likely will continue to work with the old deployment, as a workaround users can patch clair-app deployment and:

1. remove the volume "certs"
2. remove the volumeMount "certs"
3. scale down the operator
4. scale up the operator

This will trigger a reconcile and everything should get back to normal.