Remove metrics event for `==0.0.0` requirements (#1346)
Remove metrics event for `==0.0.0` requirements (#1346)

Since:
- there are many invalid styles of requirements specifiers users can
   use, and we don't special-case metrics for any of the others
- the `==0.0.0` case is an old issue due to an Ubuntu quirk that doesn't
  occur much any more now
- metrics aren't working at the moment anyway, until we implement
  `bin/report` for Honeycomb
heroku/heroku-buildpack-python,heroku/heroku-buildpack-python,Scalingo/python-buildpack,Scalingo/python-buildpack