Use SupplementalGroups from BackrestStorage for pgBackRest repository

The code was using the SupplementalGroups from the PrimaryStorage
attribute on the CRD, which may have gone unnoticed for awhile for
a host of reasons.

Author: Jonathan S. Katz

operator/backrest/repo.go

@@ -115,7 +115,7 @@ func CreateRepoDeployment(clientset *kubernetes.Clientset, namespace string, clu
 		PgbackrestS3EnvVars:   operator.GetPgbackrestS3EnvVars(*cluster, clientset, namespace),
 		Name:                  serviceName,
 		ClusterName:           cluster.Name,
-		SecurityContext:       util.GetPodSecurityContext(cluster.Spec.PrimaryStorage.GetSupplementalGroups()),
+		SecurityContext:       util.GetPodSecurityContext(cluster.Spec.BackrestStorage.GetSupplementalGroups()),
 		PodAntiAffinity: operator.GetPodAntiAffinity(cluster,
 			crv1.PodAntiAffinityDeploymentPgBackRest, cluster.Spec.PodAntiAffinity.PgBackRest),
 		PodAntiAffinityLabelName: config.LABEL_POD_ANTI_AFFINITY,