cros_sdk: enable pid ns by default

Now that the ccache issue is fixed, we can enable pid namespaces.

BUG=chromium:411984
TEST=`cros_sdk -- ps aux` shows pid ns being used
TEST=pre-cq passed

Change-Id: Icbe74dc3444dd959ec591a4a0d3eb7b36f514845
Reviewed-on: https://chromium-review.googlesource.com/230531
Reviewed-by: David James <davidjames@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_sdk.py b/scripts/cros_sdk.py
index bb4aeb3..54d27b9 100644
--- a/scripts/cros_sdk.py
+++ b/scripts/cros_sdk.py
@@ -485,10 +485,8 @@
   group.add_option('--proxy-sim', action='store_true', default=False,
                    help='Simulate a restrictive network requiring an outbound'
                         ' proxy.')
-  # TODO(vapier): Turn off pid ns until ccache issues can be fixed.
-  # http://crbug.com/411984
   group.add_option('--no-ns-pid', dest='ns_pid',
-                   default=False, action='store_false',
+                   default=True, action='store_false',
                    help='Do not create a new PID namespace.')
 
   # Internal options.