Edit existing SID<->UID / SID <->GID entries

[Kenny Dinh]

Hello,

My setup uses a custom script to specify the rule for mapping SID to
UID/GID.
I noticed in Samba (possibly 3.6.x), 4.1.x, 4.2.x, and 4.3.x, the ability
to modify UID/GID of an existing mapping has been removed.

- The options "--set-uid-mapping" and "--set-gid-mapping" in wbinfo has
been remove and it now returns NOT_IMPLEMENTED.

- "net idmap setmap" has not yet been implemented.

For Samba running as a member server, it seems there is no way to change
the UID/GID of an existing entry.  I saw Michael Adam's change that removed
those abilities but I could not find the reasoning behind that.

The only way I can see to work around this issue is to delete the existing
entry (for example SID-1-2-3) and update the custom idmapping script to
account for that particular SID.

Could some shed some light on why we no longer support ability to edit an
existing mapping?

Thank you!