Push more default options to the Python object level as they are rarely changed. These are the changes that Steve was working on.

src/python/m5/objects/DiskImage.py:
src/python/m5/objects/Ethernet.py:
src/python/m5/objects/Ide.py:
src/python/m5/objects/Tsunami.py:
    Push more default options to the Python object level as they are rarely changed.

--HG--
extra : convert_revision : 963eb7a34cd04529b3c5f24b92904ab725c93efb

src/python/m5/objects/DiskImage.py

@@ -10,6 +10,6 @@ class RawDiskImage(DiskImage):
 
 class CowDiskImage(DiskImage):
     type = 'CowDiskImage'
-    child = Param.DiskImage("child image")
+    child = Param.DiskImage(RawDiskImage(read_only=True),
+                            "child image")
     table_size = Param.Int(65536, "initial table size")
-    image_file = ''