Merge pull request dotnet/core-setup#3866 from eerhardt/DevTimeFixes
authorWes Haggard <weshaggard@users.noreply.github.com>
Wed, 21 Mar 2018 19:00:23 +0000 (12:00 -0700)
committerGitHub <noreply@github.com>
Wed, 21 Mar 2018 19:00:23 +0000 (12:00 -0700)
Add prerelease check to vswhere to support dogfood VS builds.

Commit migrated from https://github.com/dotnet/core-setup/commit/40804e41ae33ea5197911ce5764f77f634261d1c


Trivial merge