[RUST][RUNTIME] nnvm test fails

[ehsanmok]

During my local dev for Rust frontend, the current runtime tests/test_nnvm fails with that is also a problem with other current PRs such as this in here.

error: failed to run custom build command for `test-nnvm v0.0.0 (/workspace/rust/tests/test_nnvm)`

process didn't exit successfully: `/workspace/rust/tests/test_nnvm/target/debug/build/test-nnvm-7757aa29dfd2f3a3/build-script-build` (exit code: 101)

--- stderr

thread 'main' panicked at 'Cannot find config for target=llvm --system-lib, workload=('dense', (4, 8, 'float32'), (16, 8, 'float32'), (16, 'float32')). A fallback configuration is used, which may bring great performance regression.

', build.rs:18:5

note: Run with `RUST_BACKTRACE=1` for a backtrace.

Previously, my local test was failing at this check_sum. This is rather strange. I'm on Rust-nightly 1.32.

@tqchen @nhynes

[nhynes]

I ran the tests in a local docker container according to the CI flow on 0806b69 but could not reproduce the bug. I'd suggest rebasing the failing PRs onto master, at the very least.

[eqy]

Interesting, the three most recently opened PRs all fail CI with this error.

[nhynes]

Well, I found the bug. Why I couldn't reproduce is a separate issue, but I'll post a fix now :)