Merge pull request dotnet/coreclr#19259 from MattGal/update-fedoras
authorMatt Galbraith <MattGal@users.noreply.github.com>
Fri, 3 Aug 2018 17:20:28 +0000 (10:20 -0700)
committerGitHub <noreply@github.com>
Fri, 3 Aug 2018 17:20:28 +0000 (10:20 -0700)
Remove Fedora 26, add Fedora 28

Commit migrated from https://github.com/dotnet/coreclr/commit/6e488e82b0d12ee0c14545cd92319ad4d8e63f95


Trivial merge