update wsapi_client to handle non-asciirequests. issue #1631

lib/wsapi_client.js

@@ -129,7 +129,7 @@ exports.post = function(cfg, path, context, postArgs, cb) {
     if (typeof postArgs === 'object') {
       postArgs['csrf'] = csrf;
       body = JSON.stringify(postArgs);
-      headers['Content-Length'] = body.length;
+      headers['Content-Length'] = Buffer.byteLength(body);
     }
 
     var req = meth.request({