braindump.sh support bundle tool commands are incorrect

[pippitt]

When using the braindump.sh tool to upload a support file I noticed a few things.
It would be good to set a namespace (though it is probably always cortex). So add something like

NAMESPACE="cortex"
kubens $NAMESPACE

This command kubectl describe po -o json -l cortex > pods.json has a few issues, at least for me.
Describe does not support different outputs types. Also my pods don't have the label cortext
I changed it to kubectl describe po -l app=cortex-demo-backend > braindump/pods-describe.json since that was the label on my backend pods
And added a command to get the pod definitions
kubectl get po -o json -l app=cortex-demo-backend > braindump/pods-get.json

Last, the tar command has both -x and -c (so extract and create, that errors). Changed to tar -zcf braindump.tar.gz braindump