DIRECMEMORY-130 - applied Chetan's patch for resetting the used memory during MMS#clear

git-svn-id: https://svn.apache.org/repos/asf/directmemory/trunk@1501182 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/directmemory-cache/src/main/java/org/apache/directmemory/memory/MemoryManagerServiceImpl.java b/directmemory-cache/src/main/java/org/apache/directmemory/memory/MemoryManagerServiceImpl.java
index fad7de7..6dc1d03 100644
--- a/directmemory-cache/src/main/java/org/apache/directmemory/memory/MemoryManagerServiceImpl.java
+++ b/directmemory-cache/src/main/java/org/apache/directmemory/memory/MemoryManagerServiceImpl.java
@@ -263,6 +263,7 @@
             allocator.clear();
         }
         allocationPolicy.reset();
+        used.set(0L);
     }
 
     protected Pointer<V> instanciatePointer( final MemoryBuffer buffer, final int allocatorIndex, final long expiresIn,