resources: fix case of nil PodAntiAffinity

Protect from case where user provided 'affinity' entry in podSettings of
smbcommonconfig but without 'podAntiAffinity' sub-entry. This in turn
would cause samba-operator a nil pointer dereference.

Fixes: #330

Signed-off-by: Shachar Sharon <ssharon@redhat.com>

internal/resources/statefulsets.go

@@ -81,9 +81,10 @@ func buildOneSmbdPerNodeAffinity(
 
  affinity := affinityForSmbPod(planner)
  if affinity == nil {
- affinity = &corev1.Affinity{
- PodAntiAffinity: &corev1.PodAntiAffinity{},
- }
+ affinity = &corev1.Affinity{}
+ }
+ if affinity.PodAntiAffinity == nil {
+ affinity.PodAntiAffinity = &corev1.PodAntiAffinity{}
  }
  affinity.PodAntiAffinity.RequiredDuringSchedulingIgnoredDuringExecution = append(
  affinity.PodAntiAffinity.RequiredDuringSchedulingIgnoredDuringExecution,