Error doesn't occur when npm installing was failed

[anseki]

The npm installing was failed (network problem, maybe), but any error doesn't occur, and a version without npm was set to using.
I think that an error should occur, but this behavior has some reason?

https://github.com/hakobera/nvmw/blob/master/nvmw.bat#L154

  if not exist %NPM_ZIP_FILE% (
    exit /b 0;
  )

  if not exist "%NPM_ZIP_FILE%" goto install_error

(And, I think that that path should be quoted.)

[hakobera]

@anseki There are no reason to that behavior. It's my mistake.
This issue is solved by #39? (Yes, it's your pull request)

[anseki]

Yes, This issue is solved. 😄 Thank you!