Pear discover channel fails

[jayvdb]

> pear channel-discover openpear.org
Error: Unable to create XML parser
Discovering channel openpear.org over http:// failed with message: channel-add: invalid channel.xml file
Trying to discover channel openpear.org over https:// instead
Error: Unable to create XML parser
Discovery of channel "openpear.org" failed (channel-add: invalid channel.xml file)

c.f. https://gitlab.com/coala/package_manager/issues/253