Don't fail!() when rustdoc fails to run
authorAlex Crichton <alex@alexcrichton.com>
Sun, 31 Aug 2014 06:19:38 +0000 (23:19 -0700)
committerAlex Crichton <alex@alexcrichton.com>
Wed, 3 Sep 2014 00:24:53 +0000 (17:24 -0700)
commitb48b54732e338d4cb7cd7eff0ad703bb083e7397
treef00f4504496109dbc5f05c44a96d6d6e5f0e49e1
parent70446f9e45c37a1b18126769f135c173a2b54e55
Don't fail!() when rustdoc fails to run

The return value of `err.output()` will be `None` if the rustdoc executable
failed to spawn, in which case we can give a more graceful error message.

Closes #481
src/cargo/ops/cargo_rustc/mod.rs