ECONNREFUSED crash since version 2.6.1

• Version: 2.6.1
• Platform: Node.js v4.2.6 on OS X 10.11.5
• Description: Description of your issue, stack traces from errors and code that reproduces the issue

The default retry strategy:

var client = redis.createClient({
    retry_strategy: function (options) {
        if (options.error.code === 'ECONNREFUSED') {
            // End reconnecting on a specific error and flush all commands with a individual error
            return new Error('The server refused the connection');
        }
...
        // reconnect after
        return Math.max(options.attempt * 100, 3000);
    }
});

Crashes since version 2.6.1

if (options.error.code === 'ECONNREFUSED')
                 ^
TypeError: Cannot read property 'code' of null

The report names no source file or test; begin with the retry_strategy callback in the Redis client configuration and trace how ECONNREFUSED reaches options.error. Reproduce the reported failure and confirm that the callback handles the null error without crashing.