Fix typo

Author: loay

lib/discovery.js

@@ -329,7 +329,7 @@ function mixinDiscovery(PostgreSQL) {
   PostgreSQL.prototype.setDefaultOptions = function(options) {
   };
 
-  PostgreSQL.prototype.setNullableProperties = function(r) {
+  PostgreSQL.prototype.setNullableProperty = function(property) {
   };
 
   PostgreSQL.prototype.getDefaultSchema = function() {