Fix server cache memory leak (#4069)

Fixes server cache memory leak on connecting to another server, by:
* Deleting XML node and file in CServerCache::StaticSaveServerCache

* Deleting XML node and file in CServerCache::LoadServerCache

Client/core/ServerBrowser/CServerCache.cpp

@@ -186,6 +186,10 @@ bool CServerCache::LoadServerCache()
 
         MapSet(m_ServerCachedMap, key, info);
     }
+
+    delete pNode;
+    delete m_pConfigFile;
+
     return true;
 }
 
@@ -302,6 +306,9 @@ void CServerCache::StaticSaveServerCache()
     XMLAccess.SetSubNodeValue(CONFIG_NODE_SERVER_INT "11", dataSet);
 
     m_pConfigFile->Write();
+
+    delete pNode;
+    delete m_pConfigFile;
 }
 
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