hardware_StorageWearoutDetect: clarify comment.

BUG=chromium:589344
TEST=None.

Change-Id: I8075a102b79560c70d7eb34d9040966a97e0c381
Reviewed-on: https://chromium-review.googlesource.com/353737
Commit-Queue: Ilja H. Friedel <ihf@chromium.org>
Tested-by: Ilja H. Friedel <ihf@chromium.org>
Reviewed-by: Puthikorn Voravootivat <puthik@chromium.org>
diff --git a/client/site_tests/hardware_StorageWearoutDetect/hardware_StorageWearoutDetect.py b/client/site_tests/hardware_StorageWearoutDetect/hardware_StorageWearoutDetect.py
index 1a32549..5f7df24 100644
--- a/client/site_tests/hardware_StorageWearoutDetect/hardware_StorageWearoutDetect.py
+++ b/client/site_tests/hardware_StorageWearoutDetect/hardware_StorageWearoutDetect.py
@@ -16,7 +16,9 @@
     The test will be failed if:
     - At least one SMART variable has value under its threshold
       or
-    - eMMC wear out status variable is in 90-100% band or higher.
+    - eMMC wear out status variable is in 90-100% band or higher (
+      DEVICE_LIFE_TIME_EST_TYP_A). Seeing this consistently means the lab
+      device may have to be replaced.
     """
 
     version = 1