improve integration test for delete kubeconfig context

[anencore94]

update the test to use exitcode as as assertion
and to print stdout for debugging easily in error
case

applying review in #6541 from @tstromberg

[k8s-ci-robot]

Hi @anencore94. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: anencore94
To complete the pull request process, please assign priyawadhwa
You can assign the PR to them by writing /assign @priyawadhwa in a comment when ready.

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[minikube-bot]

Can one of the admins verify this patch?

[codecov-io]

Codecov Report

Merging #6567 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #6567   +/-   ##
======================================
  Coverage    38.1%   38.1%           
======================================
  Files         137     137           
  Lines        8690    8690           
======================================
  Hits         3311    3311           
  Misses       4963    4963           
  Partials      416     416

[medyagh]

/ok-to-test

[minikube-pr-bot]

All Times Minikube (PR 6567): [ 90.721591 93.736556 94.804227]
All Times minikube: [ 90.903791 89.846395 92.489968]

Average minikube: 91.080051
Average Minikube (PR 6567): 93.087458

Averages Time Per Log

+----------------------+-----------+--------------------+
|         LOG          | MINIKUBE  | MINIKUBE (PR 6567) |
+----------------------+-----------+--------------------+
| minikube v           |  0.199502 |           0.198473 |
| Creating kvm2        | 19.576529 |          20.419145 |
| Preparing Kubernetes | 48.760061 |          49.174362 |
| Pulling images       |           |                    |
| Launching Kubernetes | 20.335313 |          21.058775 |
| Waiting for cluster  |  0.218106 |           0.076175 |
+----------------------+-----------+--------------------+

[medyagh]

Thank you I tested the new command format for kubectl and it works !
with what I have on my machine "kubectl v1.17.2"
I like this PR makes its more simple and more obvious what went wrong

medya@~/workspace/minikube (crio_runtime) $ kubectl config get-contexts p2
CURRENT   NAME   CLUSTER   AUTHINFO   NAMESPACE
*         p2     p2        p2         
medya@~/workspace/minikube (crio_runtime) $ kubectl config get-contexts x4
CURRENT   NAME   CLUSTER   AUTHINFO   NAMESPACE
error: context x4 not found