Regression: separated config for index.html source and output #3289

angular-cli: 1.0.0-beta.21 patched webpack config to support pug
node: 7.2.0
os: linux x64
The patch is simply a dirty version of #2205.

I have configured like this so pug is compiled:
"index": "index.pug"
However, this also changes the output extension, which not only doesn't make sense but also breaks development server(ng serve).

Random notes:
webpack dev-server seems to have index.html hardcoded, and it's the default for most static servers too.