NullPointerException in AbstractRecord.getLockCount
We found the following exception in our cluster logs this morning. This looks to be a concurrency edge case - getLockCount is relying on a volatile variable being non-null.

This was found on Hazelcast 2.1 with the Sun JDK 1.6.0_31 i386 on CentOS 5.8 x86_64.

```
java.lang.NullPointerException
    at com.hazelcast.impl.AbstractRecord.getLockCount(AbstractRecord.java:417)
    at com.hazelcast.impl.AbstractRecord.isEvictable(AbstractRecord.java:153)
    at com.hazelcast.impl.CMap.startCleanup(CMap.java:1332)
    at com.hazelcast.impl.ConcurrentMapManager$4.run(ConcurrentMapManager.java:431)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)
```
