improve error handling in getNCCLVersion in NCCLUtils (#27883)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/27883
Returns early if NCCL version code returned to us is < 100, to prevent
division errors. This shouldn't actually happen since the nvidia nccl version is way past 0.1.0 but nice to have this safeguard.
ghstack-source-id: 91861083
Test Plan: Follow same process as https://github.com/pytorch/pytorch/pull/27068. Also force version to be < 100 and ensure that "Unknown NCCL Version" is returned.
Differential Revision: D17903234
fbshipit-source-id: c4df63bb1c18f1b2ef9e4cd434d4ca6c5ac556df
