Revert "Skip changeset discussions unless requested"

[mmd-osm]

See discussion in #401. This PR was causing regressions, since the "comments_count" header attribute did not show the acutal number of changeset comments.

comments_count="0" should be "1" here:

<?xml version="1.0" encoding="UTF-8"?>
<osm version="0.6" generator="CGImap 0.9.1 (2193678 spike-06.openstreetmap.org)" copyright="OpenStreetMap and contributors" attribution="http://www.openstreetmap.org/copyright" license="http://opendatacommons.org/licenses/odbl/1-0/">
 <changeset id="79214306" created_at="2020-01-05T14:39:30Z" closed_at="2020-01-05T14:40:09Z" open="false" user="Chenshi" uid="114430" min_lat="52.3942212" min_lon="8.1937004" max_lat="52.9121770" max_lon="9.2001523" comments_count="0" changes_count="5343">
  <tag k="comment" v="maxspeed"/>
  <tag k="created_by" v="JOSM/1.5 (15553 de)"/>
  <tag k="source" v="datenbestandbearbeitung"/>
 </changeset>
</osm>

Reverts #388