bug#26786: [PATCH] gnu: emacs-org: Update to 20170502.

[Arun Isaac]

>> I think we should build directly from org's release tarball at
>> http://orgmode.org/org-9.0.6.tar.gz instead of using the ELPA
>> tarball. It somehow feels like we are not building from source but
>> rather relying on a prepackaged tarball from ELPA. However, Nicolas
>> Goaziou, the org mode maintainer,
>> disagrees. 
>> https://lists.gnu.org/archive/html/guix-devel/2016-08/msg01395.html
>
> I find Nicolas’s argument above (that building from ELPA makes the
> recipe trivial) pretty convincing.
>
> Why would you suggest using the tarball from orgmode.org?

It seems like we are depending on an intermediary (ELPA) instead of
directly building from the original source. I feel that Guix packages
should not depend on other repositories (like ELPA).