Restore NONE as an enum value for typedef community-type

[dplore]

Proposed fix for #945

Change Scope

In the current OC models, there is ambiguity regarding how to use send-community-type to disable sending any communities at the bgp global, peer-group and neighbor levels. The OC model description says the lack of the send-community-type node means communities should not be sent. This is in conflict with the expected inheritance from global, peer-group and neighbor levels in BGP configuration. With inheritance, the lack of a node means to inherit the configuration from the next higher level.

It was proposed in #945 that an explicitly defined send-community-type as an empty list could be used to indicate no communities should be sent. But this is problematic for some encodings and likely toolchains because RFC7590 states that XML encoded yang simply omits empty lists (ref).

This proposal removes the deprecated status from the NONE value of the community-type enum.

[OpenConfigBot]

No major YANG version changes in commit 0426df8

[s19nal]

as discussed at OC operators meeting - removing a deprecated status from one enum in the leaf looks to be ok although it might be slightly contentious to call it non-breaking.
However re-instating the deprecated NONE enum solves the problem that was introduced by removing it in the first place, so I'm happy :)

[dplore]

Last call for Sep 20, 2024

[nokia1adam]

@dplore, thanks for resolving this issue.