Pass existing DS to updateDaemonSetStatus in updateDaemonSet when no change is required

[mantoine96]

What does this PR do?

This PR fixes #93

In updateDaemonSet, we create a new daemonset before checking if we need to make an update to the daemonset. Unfortunately, instead of passing the existing DS to the updateDaemonSetStatus method, we were passing the new one, which obviously had no containers running, resulting in the Agent having its status stuck in Progressing (0/0/0).

Once we pass the existing DS, the status updates as expected.

Motivation

Fixing my own issue

Additional Notes

[codecov-commenter]

Codecov Report

Merging #94 into master will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master      #94   +/-   ##
=======================================
  Coverage   57.23%   57.23%           
=======================================
  Files          31       31           
  Lines        4165     4165           
=======================================
  Hits         2384     2384           
  Misses       1600     1600           
  Partials      181      181           

Flag	Coverage Δ
#unittests	57.23% <0.00%> (ø)

Impacted Files	Coverage Δ
pkg/controller/datadogagent/agent.go	48.93% <0.00%> (ø)

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[ahmed-mez]

🙇