Apply fix for problems with LRUCache not properly cleaning up after itself.  
Fixes [AMQNET-AMQNET-521]. (See https://issues.apache.org/jira/browse/AMQNET-AMQNET-521)

diff --git a/src/main/csharp/Util/LRUCache.cs b/src/main/csharp/Util/LRUCache.cs
index ec3d7b9..0fcdb90 100644
--- a/src/main/csharp/Util/LRUCache.cs
+++ b/src/main/csharp/Util/LRUCache.cs
@@ -47,6 +47,7 @@
 		public void Clear()
 		{
 			dictionary.Clear();
+            entries.Clear();
 		}
 
         public int Count
@@ -65,12 +66,12 @@
 			get { return dictionary[key]; }
 			set 
 			{ 
-				TValue currentValue = default (TValue);
+				TValue currentValue;
 				// Moved used item to end of list since it been used again.
 				if (dictionary.TryGetValue(key, out currentValue))
 				{
 					KeyValuePair<TKey, TValue> entry = 
-						new KeyValuePair<TKey, TValue>(key, value);
+                        new KeyValuePair<TKey, TValue>(key, currentValue);
 					entries.Remove(entry);
 				}