fix; allow undefined for min/max validators (Fix #3539)

Author: vkarpov15

lib/schema/number.js

@@ -92,7 +92,7 @@ SchemaNumber.prototype.min = function(value, message) {
     msg = msg.replace(/{MIN}/, value);
     this.validators.push({
       validator: this.minValidator = function(v) {
-        return v === null || v >= value;
+        return v == null || v >= value;
       },
       message: msg,
       type: 'min',
@@ -146,7 +146,7 @@ SchemaNumber.prototype.max = function(value, message) {
     msg = msg.replace(/{MAX}/, value);
     this.validators.push({
       validator: this.maxValidator = function(v) {
-        return v === null || v <= value;
+        return v == null || v <= value;
       },
       message: msg,
       type: 'max',