Add compatibility with Node 4 for Http Status Codes
Add compatibility with Node 4 for Http Status Codes

Moving between Node 0.12 and 4 introduces different http status code
messages for the request body size is too large error (413). This should
normalize between the two, picking the one that is not undefined.

kusor/node-restify,sean3z/node-restify,gergelyke/node-restify,restify/node-restify,myroid/node-restify,hekike/node-restify,myroid/node-restify,restify/node-restify,mcavage/node-restify