tlsdate: Fix unused but set variable.

clang may warn about this when assertions are off.

BUG=b:227655984
TEST=CQ

Change-Id: I17cab4998cc833c6525c6cdc86d6fb7b43f7deb6
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/tlsdate/+/3610215
Reviewed-by: Hugo Benichi <[email protected]>
Reviewed-by: Mattias Nissler <[email protected]>
Tested-by: Michael Benfield <[email protected]>
1 file changed