lock: fix closure calls.

lib/utils/lock.js

@@ -43,7 +43,7 @@ function Lock(named) {
 
 Lock.create = function create(named) {
   var lock = new Lock(named);
-  return function lock(arg1, arg2) {
+  return function _lock(arg1, arg2) {
     return lock.lock(arg1, arg2);
   };
 };
@@ -278,7 +278,7 @@ function MappedLock() {
 
 MappedLock.create = function create() {
   var lock = new MappedLock();
-  return function lock(key, force) {
+  return function _lock(key, force) {
     return lock.lock(key, force);
   };
 };