Fix a typo

s/chromeos_chroot/chromeos_root in AbandonCLs.

BUG=chromium:1067029
TEST=unit tests

Change-Id: Ie3727aaf3b10e196f2abe4a9d90db2f6766a42a5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2173246
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: George Burgess <gbiv@chromium.org>
diff --git a/auto_delete_nightly_test_data.py b/auto_delete_nightly_test_data.py
index 8f15654..4ec5b0f 100755
--- a/auto_delete_nightly_test_data.py
+++ b/auto_delete_nightly_test_data.py
@@ -199,7 +199,7 @@
     return 0
 
   return ce.ChrootRunCommand(
-      chromeos_chroot, abandon_cls_cmd, print_to_console=False)
+      chromeos_root, abandon_cls_cmd, print_to_console=False)
 
 
 def Main(argv):