Updating reno guideline in devref to reflect latest discussion at the
IRC meeting:
<smcginnis> We really only need release notes for things that would be
good to tell deployers and end users.
<smcginnis> Internal technical details would just be confusing to most
of them, so they definitely should not have a RL.
This commit removes the line stating that we should add a release note
with the driver interfaces changes.
Change-Id: Ibcca37c85e544aa7783bc08cefd1833af87acd5d
619d28bc45