Issue #2379883 by Alan Evans, Jeremy: fix broken logic and order of precedence...

Issue #2379883 by Alan Evans, Jeremy: fix broken logic and order of precedence error in lock_acquire so lock renewal works correctly

memcache-lock-code.inc

@@ -39,7 +39,7 @@ function lock_acquire($name, $timeout = 30) {
   if (dmemcache_add($name, _lock_id(), $timeout, 'semaphore')) {
     $locks[$name] = _lock_id();
   }
-  elseif ($result = dmemcache_get($name, 'semaphore') && isset($locks[$name]) && $locks[$name] == _lock_id()) {
+  elseif (($result = dmemcache_get($name, 'semaphore')) && isset($locks[$name]) && $locks[$name] == $result) {
     // Only renew the lock if we already set it and it has not expired.
     dmemcache_set($name, _lock_id(), $timeout, 'semaphore');
   }