* elmo-shimbun.el (elmo-shimbun-folder-entity-hash): Use

* elmo-shimbun.el (elmo-shimbun-folder-entity-hash): Use
`elmo-folder-list-message-entities' instead of
`elmo-msgdb-get-overview'.
(elmo-map-folder-list-message-locations): Ditto.

* elmo-msgdb.el (elmo-msgdb-append): Rewrite (use interface
methods instead of treat directly).
(elmo-msgdb-clear): Ditto.
(elmo-msgdb-delete-msgs): Ditto.
(elmo-msgdb-sort-by-date): Ditto.

* elmo-nntp.el (elmo-nntp-msgdb-create-message): Removed unused
local variables.
(elmo-nntp-folder-msgdb-create): Follow the API change.