[Dovecot] Segfault when opening a public folder, dovecot 1.1 beta4

[Adam McDougall]

    If you don't need the other groups in Dovecot you can get rid of them and 
    just have the process use the user's primary group and mail_extra_groups. I 
    think this should work:
    
    userdb passwd {
      args = system_user=
    }
  
  Actually, yes I like this alot and put this change into production.  I was 
  planning on using some secondary groups to prevent filesystem access, but
  I can accomplish the same protection easier with this and mail_extra_groups.
  Thanks!  I didn't test yet that the secondary groups aren't loaded but I will
  sometime.

According to my logs, it seems it does not prevent the secondary groups.
I'd look at the code to see how it works, but I have to switch tasks and
may not work more with dovecot until tomorrow.  I suppose if I cannot get
this to work, it sounds like I may be able to depend on the patch below.
    
  >> With some recent permission changes I've
  >> done (affects dovecot 1.0 as well), I get a good amount of these fchown 
  >> errors
  >> and I was thinking of muting them so they do not fill my log, since they 
  >> are harmless
  >> in my setup.
    
    If these errors happen for index files Dovecot currently fallbacks to using 
    in-memory indexes.
  
  Oh. Ugh. That might explain why the indexes don't always seem to load.
  For some reason I thought dovecot might print a message when it falls back
  to in-memory indexes; would that be possible?
    
  >> Right now in my public folder permission scheme, the only thing I need
  >> dovecot-shared for (I think) is making client-added emails world-readable 
  >> at least
  >> (currently actually mode 666).  As long as the indexes are accessible by 
  >> the user,
  >> I don't care what mode or group they are.
    
    How about this: http://hg.dovecot.org/dovecot/rev/0dd9b91fd52c
  
  I will roll that in and test alongside the next patch you sent.  Thanks.