Avoid rm -v in fixtures for portability

This removes `-v` from an `rm -R` command in `make_basic_repo.sh`,
which can cause tests that needed to run that fixture to fail on
systems where `rm` does not support `-v`.

The script generates a fixtured used in numerous tests, and it is
always run even if `GIX_TEST_IGNORE_ARCHIVES` is not set, since its
output is `.gitignore`d. Because the script is so heavily used,
this change allows many more tests to pass on systems where `rm`
does not recognize `-v` than before.

`rm -v` is actually POSIX, but it was standardized very recently,
in 1003.1-2024; it was not even required in 1003.1-2017. Some Unix
systems' `rm` commands do not recognize `-v`. This includes most
(or all?) illumos and Solaris systems (except when `/usr/gnu/bin`
is present and placed early in the `$PATH`). It seems likely that
there are a number of other such systems.

Regarding the history of `rm -v` in POSIX, see:

- https://pubs.opengroup.org/onlinepubs/9699919799/utilities/rm.html
- https://pubs.opengroup.org/onlinepubs/9799919799/utilities/rm.html
- https://www.austingroupbugs.net/view.php?id=1154
- https://www.austingroupbugs.net/view.php?id=1365
- https://www.austingroupbugs.net/view.php?id=1487

Based on a `git grep -En 'rm( -[^v ;&|]*)+v'` search, this
occurrence in `make_basic_repo.sh` appears to be the only place
where `-v` is passed to `rm` in any gitoxide fixture script.

Two nearby similar, conceptually related commands omit `-v`, and
when this command (rather, the command that turned into it) was
introduced in the first version of the script in a4cec4a (#399),
another such command without `-v` was also present. This suggests
that `-v` may have been used for exploratory purposes during
development, such that the approach here of omitting `-v` it
without replacing it with anything might be sufficient.

However, it is possible for information shown when the fixture
script runs and fails to be less informative as a result of this
omission. An alternative approach to the one taken here could be to
have the script carry out a tiny experiment to check if `-v` is
supported, then use it only if it was found to be accepted.
(Another option could be to use `find` with both `-print` and
`-delete`, though that might be stronger than desired given that
the affected `rm` command does not pass `-f`.)

Author: EliahKagan

gix-discover/tests/fixtures/make_basic_repo.sh

@@ -35,7 +35,7 @@ rm -R worktrees/c-worktree-deleted
 (cd bare.git
   git worktree add ../worktrees/from-bare/c
   git worktree add ../worktrees/from-bare/d-private-dir-deleted
-  rm -R -v ./worktrees/d-private-dir-deleted
+  rm -R ./worktrees/d-private-dir-deleted
 )
 
 git clone --bare --shared . bare-no-config.git