CURLOPT_EXPECT_100_TIMEOUT_MS(3) on macOS

The text 462989aa94ec, as macOS 10.12.5, macOS 10.12.4, macOS 10.12.3, macOS 10.12.2, macOS 10.12.1, macOS 10.12 shipped it.

timeout for Expect: 100-continue response

CURLOPT_EXPECT_100_TIMEOUT_MS(3) on macOS now