Fix regression in 1c9b02233631b0ba9b096d79bf5b8d71a370dbb0.

[email protected]
[email protected]
BUG=587694
NOTRY=true

Review URL: https://codereview.chromium.org/1862503002 .

Cr-Commit-Position: refs/heads/master@{#385057}
diff --git a/build/write_build_date_header.py b/build/write_build_date_header.py
index de1b443..6fe514f 100755
--- a/build/write_build_date_header.py
+++ b/build/write_build_date_header.py
@@ -94,7 +94,7 @@
       # invalidation to not happen exactly at midnight. Use the same calculation
       # as the day before.
       # See //base/build_time.cc.
-      now = now - datetime.timedelta(day=1)
+      now = now - datetime.timedelta(days=1)
     now = datetime.datetime(now.year, now.month, now.day, 5, 0, 0)
     build_date = GetBuildDate(args.build_type, now)