[Dovecot] sieve multi-line parser bug

[info]

Dear sirs

Thank you and congratulations for creating Dovecot.

When a message header is split along several lines, it seems only the
first one is parsed by sieve.

The following header:

From:
"=?iso-8859-1?Q?Cotiatododia=20-=20O=20Jornal=20de=20Not=EDcias=20a=20Se?=
    =?iso-8859-1?Q?rvi=E7o=20de=20Cotia=20e=20Regi=E3o=2E?="
<newsletter at cotiatododia.com.br>

was not discarded by the following rule (when it should have been due to
"cotiatododia"):

if anyof (header :contains ["From", "Reply-To", "To", "Cc"]
["cotiatododia", "ganhedinheiro.com", "1000deaths.com", "ione.correia",
"nsbezerra", "estudenoexterior.com", "pestana at mauriciopestana.com.br",
"institutojairmoura2 at gmail.com", "webmaster at ie.org.br",
"jahgor at jahgor.com.br", "marketing at mirostur.com.br"], header :contains
"Subject" "E ai!, Essa voce Tem que Ver!") {
         discard;
}


Thank you,
Dennis