Show all global flags in options command

[linkvt]

Fixes #5117
Before this fix the flags shown in minikube options were taken from a list of options (viperWhiteList) which seems a bit arbitrary to me with no background.
I still don't know for sure why this is done but taking all PersistentFlags (persistent=apply to all sub commands) from the root command seems like the correct way.

This doesn't fix the problem as described in the issue but keeps it consistent with e.g. kubectl, which also shows global flags only with the options command.

Before

 $ minikube version && minikube options
minikube version: v1.9.0
commit: 48fefd43444d2f8852f527c78f0141b377b1e42a
The following options can be passed to any command:

      --alsologtostderr=false: log to standard error as well as files
      --log_dir='': If non-empty, write log files in this directory
  -v, --v=0: log level for V logs

After

 $ make && out/minikube version && out/minikube options
make: `out/minikube' is up to date.
minikube version: v1.9.0
commit: b47e8d502fb62ec0a968c47e75414aeadf125b4d
The following options can be passed to any command:

      --alsologtostderr=false: log to standard error as well as files
  -b, --bootstrapper='kubeadm': The name of the cluster bootstrapper that will set up the kubernetes cluster.
      --log_backtrace_at=:0: when logging hits line file:N, emit a stack trace
      --log_dir='': If non-empty, write log files in this directory
      --logtostderr=false: log to standard error instead of files
  -p, --profile='minikube': The name of the minikube VM being used. This can be set to allow having multiple instances of minikube independently.
      --stderrthreshold=2: logs at or above this threshold go to stderr
  -v, --v=0: log level for V logs
      --vmodule=: comma-separated list of pattern=N settings for file-filtered logging

[k8s-ci-robot]

Hi @linkvt. 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[minikube-bot]

Can one of the admins verify this patch?

[medyagh]

/ok-to-test

[minikube-pr-bot]

Error: running mkcmp: exit status 1

[medyagh]

@linkvt thank you for fixing this !