More Python hacking to deal with config.py split

and resulting recursive import trickiness.

--HG--
extra : convert_revision : 1ea93861eb8d260c9f3920dda0b8106db3e03705

src/python/m5/objects/MemTest.py

@@ -1,4 +1,5 @@
-from m5.config import *
+from m5.SimObject import SimObject
+from m5.params import *
 class MemTest(SimObject):
     type = 'MemTest'
     cache = Param.BaseCache("L1 cache")