[PATCH] Configuration for source-fetching command needs documentation

[Garrett Holmstrom]

The fourth part of allowed_scm tuples in kojid.conf that specifies
what command to run in lieu of ``make sources'' isn't documented.
Attached is a patch that describes it in kojid.conf's commentary
alongside the rest of allowed_scm's documentation.

The patch is copypasted from bug 679897, which is a few months old
now, so I apologize if it no longer applies perfectly cleanly.

--
Garrett Holmstrom