Add error handler from getConnection to query

lib/dialects/mysql/connector-manager.js

@@ -184,6 +184,9 @@ module.exports = (function() {
     });
 
     this.getConnection(options, function (err, client) {
+      if (err) {
+        return query.emit('error', err)
+      }
       query.client = client
       query.run(sql)
     });