Remove obsoleted files and config variables

* Updated a comment in schema.py to reference $wgEventLoggingSchemaApiUri
  rather than $wgEventLoggingSchemaIndexUri.
* Deleted old sample supervisor configuration file. The recommended way of
  managing EventLogging daemons is Upstart, using the job configurations that
  are bundled with the 'eventlogging' module in operations/puppet.

Change-Id: I0d50630cd9a5e486085e15ad2358382271513f07