[Fix] URL redirector: Fix call to is_redirector
[Fix] URL redirector: Fix call to is_redirector

 - Reported by: @dehnli

AlexeySa/rspamd,AlexeySa/rspamd,AlexeySa/rspamd,AlexeySa/rspamd,AlexeySa/rspamd,AlexeySa/rspamd,AlexeySa/rspamd,AlexeySa/rspamd,AlexeySa/rspamd