Fix dns uncaught exception

[chutiphon-k]

Fix case receive uncaught exception error when cannot call dns server which is the cause of node server down.

ex:

Error: getaddrinfo ENOTFOUND api.omise.co api.omise.co:443
    at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:57:26)

fix by handle event error in function _responseHandler

omise-node/lib/api.js

Lines 13 to 36 in bce1acb

	function _responseHandler(req) {
	return new Promise(function(resolve, reject) {
	req.on('response', function(res) {
	var resp = '';
	res.setEncoding('utf8');
	res.on('data', function(chunk) {
	resp += chunk;
	});
	res.on('end', function() {
	try {
	logger.log('info', resp);
	resp = JSON.parse(resp);
	if (resp.object === 'error') {
	reject(resp);
	} else {
	resolve(resp);
	}
	} catch (err) {
	reject(err);
	}
	});
	});
	});
	}

function _responseHandler(req) {
  return new Promise(function(resolve, reject) {
    req
      .on('response', function(res) {
        var resp = '';
        res.setEncoding('utf8');
        res.on('data', function(chunk) {
          resp += chunk;
        });
        res.on('end', function() {
          try {
            logger.log('info', resp);
            resp = JSON.parse(resp);
            if (resp.object === 'error') {
              reject(resp);
            } else {
              resolve(resp);
            }
          } catch (err) {
            reject(err);
          }
        });
      })
      .on('error', function(err) {  // add this line
        reject(err);
      });
  });
}

[varshard]

Thank you.

[varshard]

@chutiphon-k I'ved open a PR for this issue.

[varshard]

The 0.5.6 release should fix this.