Qualify calls to cartodb extension so having it in the search_path isn't necessary

lib/backends/dataview.js

@@ -8,7 +8,7 @@ var DataviewFactoryWithOverviews = require('../models/dataview/overviews/factory
 const dbParamsFromReqParams = require('../utils/database-params');
 var OverviewsQueryRewriter = require('../utils/overviews-query-rewriter');
 var overviewsQueryRewriter = new OverviewsQueryRewriter({
-    zoom_level: 'CDB_ZoomFromScale(!scale_denominator!)'
+    zoom_level: 'cartodb.CDB_ZoomFromScale(!scale_denominator!)'
 });
 
 var dot = require('dot');

lib/backends/overviews-metadata.js

@@ -12,9 +12,9 @@ OverviewsMetadataBackend.prototype.getOverviewsMetadata = function (username, sq
     // FIXME: Currently using internal function _cdb_schema_name
     //        CDB_Overviews should provide the schema information directly.
     const query = `
-      SELECT *, _cdb_schema_name(base_table)
-        FROM CDB_Overviews(
-            CDB_QueryTablesText($windshaft$${queryUtils.substituteDummyTokens(sql)}$windshaft$)
+      SELECT *, cartodb._cdb_schema_name(base_table)
+        FROM cartodb.CDB_Overviews(
+            cartodb.CDB_QueryTablesText($windshaft$${queryUtils.substituteDummyTokens(sql)}$windshaft$)
         );
     `;
     this.pgQueryRunner.run(username, query, function handleOverviewsRows(err, rows) {