[Dovecot] [dovecot-2.1.15] mdbox corruption, doveadm force-resync can't repair it (throws segfault)

[Marcin Mirosław]

clang static analyzer also suspect dereference of null pointer in
mdbox-storage-rebuild.c 433 (if you can't have fresh analyse here it is:
http://mejor.pl/clang-analysis/dovecot-2.15/ )