[Dovecot] doveadm table formatter: hidden titles may cause misaligned headers

Hello,

I recently noticed a small bug in the doveadm table formatter: hidden titles may cause the headers to be misaligned. The behavior in question was introduced by commit http://hg.dovecot.org/dovecot-2.2/rev/210282ae46e1 and doveadm -f table quota get -A may be used to reproduce it.

Most simple patch attached: it simply restores the old behavior, to some extent. Actually hiding those titles may be desired.

Regards, Julian Reich