Updated Travis build to generate for all Linux runtimes.
Updated Travis build to generate for all Linux runtimes.

nabychan/omnisharp-roslyn,DustinCampbell/omnisharp-roslyn,OmniSharp/omnisharp-roslyn,DustinCampbell/omnisharp-roslyn,jtbm37/omnisharp-roslyn,hal-ler/omnisharp-roslyn,OmniSharp/omnisharp-roslyn,hal-ler/omnisharp-roslyn,jtbm37/omnisharp-roslyn,nabychan/omnisharp-roslyn