Fix CID 1255187, 1255202, 1255213, 1255260, 1255308

Change-Id: If2357dc8e6147b2f1983f646e4f3ba70195e59ff
Reviewed-on: https://review.haiku-os.org/c/85
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
Reviewed-by: Stephan Aßmus <superstippi@gmx.de>

headers/private/userlandfs/shared/HashMap.h

@@ -23,14 +23,16 @@ public:
 	HashMapElement()
 		:
 		fKey(),
-		fValue()
+		fValue(),
+		fNext(NULL)
 	{
 	}
 
 	HashMapElement(const Key& key, const Value& value)
 		:
 		fKey(key),
-		fValue(value)
+		fValue(value),
+		fNext(NULL)
 	{
 	}