ActivityMonitor: fixed minor issue CID 609788.

* If the circular buffer was created with a size of zero, fBuffer would
  be freed without being initialized.

src/apps/activitymonitor/CircularBuffer.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2009, Axel Dörfler, [email protected].
+ * Copyright 2008-2013, Axel Dörfler, [email protected].
  * Distributed under the terms of the MIT License.
  */
 #ifndef CIRCULAR_BUFFER_H
@@ -16,7 +16,8 @@ class CircularBuffer {
 public:
 	CircularBuffer(size_t size)
 		:
-		fSize(0)
+		fSize(0),
+		fBuffer(NULL)
 	{
 		SetSize(size);
 	}
@@ -96,4 +97,5 @@ private:
 	Type*		fBuffer;
 };
 
+
 #endif	// CIRCULAR_BUFFER_H