Fix icu link warning on Windows

BUG=325982
TEST=run builds with and without component=shared_library and verify no linker warning are emitted. Run net_unittests --gtest_filter=NetUtil*.*
R=jshin@chromium.org

Review URL: https://codereview.chromium.org/117663003

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/icu46@243425 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
3 files changed