Remove incomplete SPARQL PATCH handler.

The PATCH handler for application/sparql does not perform any patching,
i.e., nothing is ever written to disk.
Since our next goal is to further abstract patching code
(which includes writing), this incomplete code cannot be used.

Author: RubenVerborgh

lib/handlers/patch.js

@@ -10,7 +10,6 @@ var $rdf = require('rdflib')
 const DEFAULT_CONTENT_TYPE = 'text/turtle'
 
 const PATCHERS = {
-  'application/sparql': require('./patch/sparql-patcher.js'),
   'application/sparql-update': require('./patch/sparql-update-patcher.js')
 }