Silent failure to build with wrong metadata

[Nemo157]

https://crates.io/crates/roslibrust/0.5.0 was published with package.metadata.docs.rs.features = "all" (this needs to be an array of strings). When attempting to build it we attempted to build 5 times, with no error message emitted to the logs or recorded to S3.

Will probably be fixed along with #797, we should just make sure that the recorded error message is useful for the crate author to diagnose.

[syphar]

solved with #2467