Fix undeclared variable

lib/cartodb/controllers/layergroup.js

@@ -516,12 +516,12 @@ function getAffectedTables (layergroupAffectedTables, pgConnection) {
             return next();
         }
 
-        const sql = [];
+        const queries = [];
         mapconfig.getLayers().forEach(function(layer) {
-            sql.push(layer.options.sql);
+            queries.push(layer.options.sql);
             if (layer.options.affected_tables) {
                 layer.options.affected_tables.map(function(table) {
-                    sql.push(`SELECT * FROM ${table} LIMIT 0`);
+                    queries.push(`SELECT * FROM ${table} LIMIT 0`);
                 });
             }
         });
@@ -529,6 +529,7 @@ function getAffectedTables (layergroupAffectedTables, pgConnection) {
         const sql = queries.length ? queries.join(';') : null;
 
         if (!sql) {
+            global.logger.warn('ERROR generating cache channel: this request doesn\'t need an X-Cache-Channel generated');
             return next();
         }
 
@@ -538,7 +539,7 @@ function getAffectedTables (layergroupAffectedTables, pgConnection) {
                 return next();
             }
 
-            QueryTables.getAffectedTablesFromQuery(connection, sql.join(';'), (err, affectedTables) => {
+            QueryTables.getAffectedTablesFromQuery(connection, sql, (err, affectedTables) => {
                 req.profiler.done('getAffectedTablesFromQuery');
                 if (err) {
                     global.logger.warn('ERROR generating cache channel: ', err);