Project initialization fails due to unrecognized keyword "platform"

dotnet-cli added"type": "platform" to project.json schema. When launching omnisharp on a project that has this in the project.json, omnisharp crashes.

eg.

{
  "version": "1.0.0-*",
  "compilationOptions": {
    "emitEntryPoint": true
  },
  "dependencies": {
    "Microsoft.NETCore.App": { "type": "platform", "version": "1.0.0-rc2-23911" }
  },
  "frameworks": {
    "netstandard1.5": { }
  }
}

The project system 'DotNetProjectSystem' threw exception during initialization.
unknown keyword platform
   at Microsoft.DotNet.ProjectModel.ProjectReader.TryGetProject(String path, Project& project, ICollection`1 diagnostics, ProjectReaderSettings settings)
   at Microsoft.DotNet.ProjectModel.WorkspaceContext.AddProjectEntry(String projectDirectory, FileModelEntry`1 currentEntry)

[DustinCampbell]

Awesome guys – should we kick off a release with this change?

[hal-ler]

I was hoping that we can validate it a bit using an editor. I had some silent failures that did not show up in the tests while making this change.