Wasm-pack: Terminal spam on windows

[tbillington]

🐛 Bug description

Output is spammed when running wasm-pack build in git bash on windows.

🤔 Expected Behavior

Less spam.

👟 Steps to reproduce

Run wasm-pack build in a project from git bash on windows.

🌍 Your environment

Include the relevant details of your environment.
wasm-pack version: 0.5.1
rustc version: rustc 1.32.0-nightly (e6c5cf923 2018-11-04)

[fitzgen]

See also https://github.com/rustwasm/wasm-pack/issues/298

[tbillington]

@fitzgen Ah, I scanned for existing issues but didn't pick up on that one, cheers.

[alexcrichton]

In addition to #298 I think this is covered by https://github.com/rustwasm/wasm-pack/issues/284 as well, so I'm going to close this in favor of those two issues