GitLab

IsControlCharacter() was checking an unsigned char to
make sure it's >= 0, which is trivially true. This throws
a warning on the default CrOS toolchain, so remove it even though it's harmless

BUG=424334
TEST=net_unittests
R=rsleevi@chromium.org

Review URL: https://codereview.chromium.org/640303008

Cr-Commit-Position: refs/heads/master@{#300170}