Errors from ready check are emitted to client handler instead of being bubbled up to caller.

• Version: 2.6.2
• Platform: Node 0.12.2 / Windows Server 2012 R2
• Description: If an error is thrown in ready check, it is emitted through the client's event handler instead of being bubbled up to the calling method.

Example:

1. Server is busy running a script.
2. ready check's call for info returns: ReplyError: BUSY Redis is busy running a script. You can only call SCRIPT KILL or SHUTDOWN NOSAVE.
3. error is emitted via:

err.message = 'Ready check failed: ' + err.message;
this.emit('error', err);

1. calling method has no chance to handle the error.

Example of how it works with ready check:

var redis = Promise.promisifyAll(require('redis'));
var client = redis.createClient(redisConfig.port, redisConfig.host);

client.on('error', function(err){ //BUSY error ends up here });

function handleError(err) { //BUSY error NEVER gets here };

client.evalAsync(cmd).then(handleReply).error(handleError);

Example of how it works with no_ready_check: true:

var redis = Promise.promisifyAll(require('redis'));
var client = redis.createClient(redisConfig.port, redisConfig.host, {no_ready_check: true});

client.on('error', function(err){ //BUSY error NEVER ends up here });

function handleError(err) { //BUSY error ends up here };

client.evalAsync(cmd).then(handleReply).error(handleError);

Shouldn't the ready check either:

1. Handle BUSY responses from the server, retrying just like it does when the server is loading data from disk.
   OR
2. Bubble the error up to the caller instead of through the client.

Trace the client's ready-check entry point and the evalAsync call path described in the issue; no source file or test is named, so locate those entry points first. Reproduce the BUSY response and confirm the chosen behavior: either retry it like loading responses or deliver it to the calling promise rather than the client error handler.