Return process from run_as_root.

lib/utils.py

@@ -28,9 +28,9 @@ def run(*args, **kwargs):
 def run_as_root(*args, **kwargs):
     """A helper for run that invokes sudo when unprivileged"""
     if os.geteuid() != 0:
-        run("sudo", *args, **kwargs)
+        return run("sudo", *args, **kwargs)
     else:
-        run(*args, **kwargs)
+        return run(*args, **kwargs)
 
 def create_disk(image, disk_type, fs_type, size):
     """Create a disk image, with a filesystem on it"""