login: Fix clang-3.9 warnings

BUG=none
TEST=daisy-release lumpy-release amd64-generic-asan x86-generic-asan

Change-Id: I1bc1f92d8b69c6a9e5803a2c4d9df1f3a9eae8ed
Reviewed-on: https://chromium-review.googlesource.com/341582
Commit-Ready: Ting-Yuan Huang <laszio@chromium.org>
Tested-by: Ting-Yuan Huang <laszio@chromium.org>
Reviewed-by: Caroline Tice <cmtice@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
1 file changed