Use improved multiply function

See https://gist.github.com/d4f70ded68e0d79c3eab

lib/mysql/auth.js

@@ -59,17 +59,12 @@ exports.hashPassword = function(password) {
 }
 
 // Provided by Herbert Vojčík, needed to deal with float point precision problems in JS
-exports.multiply = function(x, y) {
-  var lowX = x & 0xffff,
-      highX = (x >> 16) & 0xffff,
-      lowY = y & 0xffff,
-      highY = (y >> 16) & 0xffff
-      result =
-        0x10000 * ((highX * lowY + lowX * highY) & 0xffff) + lowY * lowX;
+exports.multiply = function(a, b) {
+  var a1 = a >>> 16,
+      a2 = a & 0xffff;
+  // Precondition: b is in 32bit range
 
-  //result = result & 0xffffffff;
-  result = result % 0x100000000;
-  return result;
+  return ((a1 * b << 16) + a2 * b) >>> 0;
 }
 
 exports.int32Write = function(buffer, number, offset) {