Fix for dotnet new mvc command

[dlipdhunter]

The template description for mvc has only two spaces separating the template name and short name. Using 3 spaces for splitting causes the short name be treated as part of template name and language is treated as the short name.
I have changed the regex to split using two spaces instead.

This is my first open source contribution ever. So let me know if I had missed to update anything.

Thanks,
Dilip