maildir: If uidlist has an empty GUID entry, log an error and remove it. This fixes an assert-crash in dsync.
maildir: If uidlist has an empty GUID entry, log an error and remove it.
This fixes an assert-crash in dsync.

LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot