firmware_Cr50Update: remove unused arg

BUG=none
BRANCH=none
TEST=none

Change-Id: Ie61a7373d81f11e163d352e5373bd51b6a3b14cb
Signed-off-by: Mary Ruthven <mruthven@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/522877
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>
diff --git a/server/site_tests/firmware_Cr50Update/firmware_Cr50Update.py b/server/site_tests/firmware_Cr50Update/firmware_Cr50Update.py
index f79871e..0f3138b 100644
--- a/server/site_tests/firmware_Cr50Update/firmware_Cr50Update.py
+++ b/server/site_tests/firmware_Cr50Update/firmware_Cr50Update.py
@@ -68,8 +68,7 @@
             self.rootfs_tool.enable()
 
         self.host = host
-        self.test = test.lower()
-        self.erase_nvmem = self.test == self.ERASE_NVMEM
+        self.erase_nvmem = test.lower() == self.ERASE_NVMEM
 
         # A dict used to store relevant information for each image
         self.images = {}