travis: Cleanup
travis: Cleanup

Use language: shell to avoid overhead of setting up ruby.
Explicitly set os and dist.
Drop sudo requirement, it has no effect.

Signed-off-by: Jan Vesely <6a2ac3bd1a50b5b4969c0b358741eeb258bebe0c@gmail.com>

numba/llvmlite,numba/llvmlite,numba/llvmlite,numba/llvmlite