When moving index file to memory, change the filename to be "(in-memory index)".
When moving index file to memory, change the filename to be "(in-memory
index)".

--HG--
branch : HEAD

jkerihuel/dovecot,jkerihuel/dovecot,dscho/dovecot,dscho/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,dscho/dovecot,dscho/dovecot,jwm/dovecot-notmuch,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,dscho/dovecot