file_cache_delete() can now safely be used with a NULL pointer.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9938 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kernel/core/cache/file_cache.cpp

@@ -1,7 +1,7 @@
 /*
-** Copyright 2004, Axel Dörfler, [email protected]. All rights reserved.
-** Distributed under the terms of the Haiku License.
-*/
+ * Copyright 2004, Axel Dörfler, [email protected]. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
 
 
 #include "vnode_store.h"
@@ -466,6 +466,9 @@ file_cache_delete(void *_cacheRef)
 {
 	file_cache_ref *ref = (file_cache_ref *)_cacheRef;
 
+	if (ref == NULL)
+		return;
+
 	vfs_vnode_release_ref(ref->device);
 	delete ref;
 }