[npm5] CLI can not add platform from local tgz package

[dtopuzov]

If you run on machine with npm 5 CLI can not add platform from local tgz package.

Steps to reproduce:

npm i -g nativescript@next
tns platform add android --path TestApp --frameworkPath tns-android.tgz

Result:

Support for Node.js 8.0.0 is not verified. This CLI might not install or run properly.

Copying template files...
Installing  /Users/topuzov/Git/nativescript-cli-tests/sut/tns-android.tgz
  ◞ Installing added 1 package in 1.165s
ENOENT: no such file or directory, open '/Users/topuzov/Git/nativescript-cli-tests/TestApp/node_modules/Users/topuzov/Git/nativescript-cli-tests/sut/tns-android.tgz/package.json'

This issues is critical for enabling CI tests with npm5.