When filling postmaster queue, include all messages, not just unsent. Bug 727679.

* src/engine/imap-db/outbox/smtp-outbox-folder.vala: Remove where clause
  from prefill query.

src/engine/imap-db/outbox/smtp-outbox-folder.vala

@@ -146,7 +146,6 @@ private class Geary.SmtpOutboxFolder : Geary.AbstractLocalFolder, Geary.FolderSu
                 Db.Statement stmt = cx.prepare("""
                     SELECT id, ordering, message
                     FROM SmtpOutboxTable
-                    WHERE sent = 0
                     ORDER BY ordering
                 """);