Merge pull request dotnet/coreclr#13876 from eerhardt/UpdateBuildTools
authorEric Erhardt <eric.erhardt@microsoft.com>
Mon, 11 Sep 2017 16:30:56 +0000 (11:30 -0500)
committerGitHub <noreply@github.com>
Mon, 11 Sep 2017 16:30:56 +0000 (11:30 -0500)
Update BuildTools automatically when new versions are available.

Commit migrated from https://github.com/dotnet/coreclr/commit/dd5c5dcb3596e0abdecb4af6ede5e280d8c884ca


Trivial merge