HttpCollector ignores "port" parameter from Collectd config

Steps to reproduce:

1. Configure a package in collectd-configuration.xml that covers a service with HTTP as its underlying transport and that is reachable on port 2102: Include a "port" parameter on the service and configure the HttpCollector to be used for the service:

...
        <service name="HttpDocCount" interval="300000" user-defined="false" status="on" >
          <parameter key="http-collection" value="doc-count" />
          <parameter key="port" value="2102" />
          <parameter key="retry" value="1" />
          <parameter key="timeout" value="2000" />
        </service>
...
<collector service="HttpDocCount" class-name="org.opennms.netmgt.collectd.HttpCollector" />

2. Configure a corresponding http-collection in http-datacollection-config.xml with no "port" attribute on the <url> element(s):

  <http-collection name="doc-count">
    <rrd step="300">
      <rra>RRA:AVERAGE:0.5:1:2016</rra>
    </rrd>
    <uris>
      <uri name="document-counts">
        <url path="/test/resources/httpcolltest.html"
             user-agent="Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en) AppleWebKit/412 (KHTML, like Gecko) Safari/412"
             matches=".*([0-9]+).*" response-range="100-399" >
        </url>
        <attributes>
          <attrib alias="documentCount" match-group="1" type="counter32"/>
        </attributes>
      </uri>
    </uris>
  </http-collection>

3. Restart OpenNMS and put the "HttpDocCount" service onto an interface where it's reachable via tcp/2102

Expected result:

Data collected and persieted via HTTP on port 2102

Actual result:

No data collected because the HttpCollector attempts to use the default port, 80.

This issue corresponds to http://mynms.opennms.com/Ticket/Display.html?id=591