When doing completion for arguments or flags for a plugin, kubectl will
call "kubectl_complete-<plugin>" to obtain the list of completions.
For example, for "krew" plugin, when the user triggers completion using:
$ kubectl krew <tab><tab>
kubectl will look for an executable file called "kubectl_complete-krew".
This file should print the list of valid completions for the plugin to
stdout. Using cobra.ShellCompDirective as the last line of the output
is supported as is done by Cobra.
We also clear global flags when doing plugin completion because plugins
don't necessarily accept the global kubectl flags. If some plugins do,
they will need to include such flags in their kubectl_complete-<plugin>
output.
Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>
Kubernetes-commit: befc8da7efa5d961d9ade4eadc706292c7ca5a64
d2df859d92