README: updated collectd_converters definition example to reflect the fact     that it expects a dict
README: updated collectd_converters definition example to reflect the fact
    that it expects a dict

ewdurbin/bucky,ewdurbin/bucky,CollabNet/puppet-bucky,CollabNet/puppet-bucky,jsiembida/bucky3,CollabNet/puppet-bucky,CollabNet/puppet-bucky,Hero1378/bucky,JoseKilo/bucky,MrSecure/bucky2,MrSecure/bucky2,Hero1378/bucky,dimrozakis/bucky,trbs/bucky,trbs/bucky,dimrozakis/bucky,JoseKilo/bucky