sidecar: Don't modify the pod phase
sidecar: Don't modify the pod phase

One decision to revisit was to see if really wanted to change the pod
phase. It was clearly agreed here that we won't:
	https://github.com/kubernetes/enhancements/pull/1913#discussion_r482212580

This commit just removes the section to discuss that (it is already
agreed) and updates the KEP to reflect that.

Signed-off-by: Rodrigo Campos <6dfa9cecb562e345739f2e4eb69e9ebd0fbff687@kinvolk.io>

kubernetes/enhancements,kubernetes/enhancements,kubernetes/enhancements