[horde] Ingo/Sieve - Vacation date range not working

[Stuart C. Naifeh]

I have Ingo set up to use a sieve backend with dovecot/sieve as the
underlying mail/sieve server.  I can create a vacation responder on Horde,
and it successfully generates the script, but if I set a date range for the
vacation responder, the script does not fire for mail coming from gmail
(which I used to test it) and likely other mail systems.

The issue is that Ingo assumes the relevant date will be in a header called
"Received."  Gmail uses X-Recieved, and mail from gmail therefore does not
have a header called Received, so the script does not match, and the
vacation responder does not fire.

One option would be to use the sieve date and relational extensions instead
of the regex extension, which would allow a rule such as:

if allof(currentdate :value "ge" "date" "2013-07-29", currentdate
:value "le" "date" "2013-08-05")