7340: Fix bundle clean issue r=deivid-rodriguez a=deivid-rodriguez
### What was the end-user problem that led to this PR?
The problem was that `bundle clean` is crashing under some conditions.
### What was your diagnosis of the problem?
My diagnosis was that sometimes (when the bundle includes git sourced gems with extensions), it assumes that some paths exist, but they don't.
### What is your fix for the problem, implemented in this PR?
My fix is to ignore those paths.
### Why did you choose this fix out of the possible options?
I chose this fix because it fixes the issue.
Fixes#7338.
Co-authored-by: David Rodríguez <deivid.rodriguez@riseup.net>
(cherry picked from commit b007fde67c77c1f15f13b97eda186644c2a2be04)
https://github.com/bundler/bundler/commit/3766053507