python: fix m5.build_env variable.

As it is now, some objects will get the incorrect value depending where they
were defined.

--HG--
extra : convert_revision : a11a14842f9524739cbf54a48be6ec051f371200

src/python/m5/__init__.py

@@ -81,11 +81,6 @@ try:
 except ImportError:
     running_m5 = False
 
-if running_m5:
-    from event import *
-    from simulate import *
-    from main import options
-
 if running_m5:
     import defines
     build_env.update(defines.m5_build_env)
@@ -93,6 +88,11 @@ else:
     import __scons
     build_env.update(__scons.m5_build_env)
 
+if running_m5:
+    from event import *
+    from simulate import *
+    from main import options
+
 import SimObject
 import params
 import objects