Icecast 'locks up' on SIGHUP if there are duplicate listener-sockets in the config

As reported by 'szett' on IRC.

Excerp of the offending config file:

<listen-socket>
   <port>8000</port>
   <!-- <bind-address>127.0.0.1</bind-address> -->
   <!-- <shoutcast-mount>/stream</shoutcast-mount> -->
</listen-socket>

<!-- SOCKET FOR SOURCES -->
 <listen-socket>
    <port>8000</port>
    <!-- <bind-address>127.0.0.1</bind-address> -->
    <!-- <shoutcast-mount>/stream</shoutcast-mount> -->
</listen-socket>