[Dovecot] PERMANENTFLAGS response if ACL seen/write rights are missing

[Michael M Slusarz]

In dovecot 2.0.13, if a user does not have either s or w ACL rights on  
a mailbox, PERMANENTFLAGS correctly indicates that the mailbox has not  
permanent flags:

* OK [PERMANENTFLAGS ()] Read-only mailbox.

However, if one is set but not the other, the PERMANENTFLAGS list is  
not being pruned appropriately.  For example, for a mailbox with the  
following flags:

* FLAGS (\Answered \Flagged \Deleted \Seen \Draft $Forwarded $Junk)

If s is set, but not w, I would expect PERMANENTFLAGS to look like:

* OK [PERMANENTFLAGS (\Seen)]

If w is set, but not s, I would expect this:

* OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Draft $Forwarded $Junk \*)]

However, in both cases I currently see all flags in the mailbox:

* OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft  
$Forwarded $Junk \*)]

michael