bug: some table header(?) output goes to stderr instead of stdout

[Marc]

[@ sbin]# doveadm -f table -o mail_location=mdbox_deleted:/home/popusers/testtest/mdbox:INDEX=/home/popindex/testtest/index fetch -u testtest 'guid' mailbox INBOX 2> /dev/null
3c967f33b8aea671f3551db1ea8e33e9
6fa01ccc103a7009c7b940657dbcd72c
ba955a6d6218950f42e5b0ee0a33a916

[@ sbin]# doveadm -f table -o mail_location=mdbox_deleted:/home/popusers/testtest/mdbox:INDEX=/home/popindex/testtest/index fetch -u testtest 'guid' mailbox INBOX
guid
3c967f33b8aea671f3551db1ea8e33e9
6fa01ccc103a7009c7b940657dbcd72c
ba955a6d6218950f42e5b0ee0a33a916