Re: [PATCH 12/29] read_raw_ref(): improve docstring

Michael Haggerty [off-list ref] writes:

  * Backend-specific flags might be set in type as well, regardless of
  * outcome.
  *
- * sb_path is workspace: the caller should allocate and free it.

All made sense.

A welcome bonus is the removal of this stale comment that 42a38cf7
(read_raw_ref(): manage own scratch space, 2016-04-07) forgot to
remove.