Update imagepullsecrets in service account on existing clusters/serviceaccounts

[nikore]

Change log description

Updates the imagePullSecrets section of the ServiceAccount on reconciliation

What the code does

Noticed when working on #383 that if I updated the imagePullSecrets setting to use a private repo it wouldn't update the ServiceAccount. This meant I would have to either manually edit the ServiceAccount or delete the cluster and make a new one.

This allows updating the imagePullSecrets section in the ServiceAccount on existing clusters.

Purpose of the change

Fixes #388

How to verify it

Deploy a zookeeper cluster, then update spec.Pod.ImagePullSecrets with a new secret and wait for the cluster to reconcile. I also added a unit test covering this use case.

[codecov]

Codecov Report

Merging #384 (dbb8d58) into master (aafd465) will decrease coverage by 0.13%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master     #384      +/-   ##
==========================================
- Coverage   86.00%   85.86%   -0.14%     
==========================================
  Files          11       11              
  Lines        1572     1578       +6     
==========================================
+ Hits         1352     1355       +3     
  Misses        147      147              
- Partials       73       76       +3     

Impacted Files	Coverage Δ
...er/zookeepercluster/zookeepercluster_controller.go	63.02% <50.00%> (-0.16%)	⬇️

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[anishakj]

@nikore Please raise an issue corresponding to this. And looks like the newly added lines are not covered by unit tests. Could you please have a look?

[nikore]

The only thing that isn't covered is the return err part of that function which there is no way for me to reach given the current test setup. The current testing seems consistent with the other tests in this file.

Codecov does a bad job at catching conditional error handling like this, if I where to change it to check error in a different line it would report it better.

[anishakj]

LGTM