Fix customer UUID filter in base resource filterset.
Fix customer UUID filter in base resource filterset.

opennode/waldur-mastermind,opennode/waldur-mastermind,opennode/nodeconductor-assembly-waldur,opennode/nodeconductor-assembly-waldur,opennode/waldur-mastermind,opennode/nodeconductor-assembly-waldur,opennode/waldur-mastermind