Fix ApiQueryLogEvents::addLogParams for unknown types using the new format

Fix ApiQueryLogEvents::addLogParams for unknown types using the new format

Fixed ApiQueryLogEvents::addLogParams for unknown (probably extension)
log types which use the new log format (with keys like 4:foo:paramname).
Until now such keys we're directly put into the XML output resulting
in invalid XML (see bug 43221, which will be fixed by this). To prevent
this we just remove everything except the plain parameter name and use that
as key for the output.

Change-Id: I1a3c7ac624eb575b879d068d47d3a13c9972b1a1