[rubygems/rubygems] Fix strange error when running `bundle add` with frozen mode set

If Gemfile is empty and there's no lockfile (situation after `bundle init`), and
`frozen` is configured, running `bundle add` will result in an strange
error, like this:

```
$ bundle add rake
, but the lockfile can't be updated because frozen mode is set

You have deleted from the Gemfile:
* rake (~> 13.2)

Run `bundle install` elsewhere and add the updated Gemfile to version control.
```

This commit fixes the problem to instead print

https://github.com/rubygems/rubygems/commit/152331a9dc

0 files changed, 0 insertions, 0 deletions