[dovecot/core] 27fdbf: plugins/fts - make storage errors more informative

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/dovecot/core
  Commit: 27fdbf79a2abd6feb7c503e46e63878c8a17127b
      https://github.com/dovecot/core/commit/27fdbf79a2abd6feb7c503e46e63878c8a17127b
  Author: Phil Carmody <phil at dovecot.fi>
  Date:   2016-10-05 (Wed, 05 Oct 2016)

  Changed paths:
    M src/plugins/fts/fts-storage.c

  Log Message:
  -----------
  plugins/fts - make storage errors more informative

There are 3 different ways to fail ending a transaction (one
of which is itself just a record that something now unknown
previously failed). Identify which one in the logs.

Signed-off-by: Phil Carmody <phil at dovecot.fi>