Some CI users (OAI developers) expressed that the warning of the `docker
volume prune` before starting RFsim is confusing. To avoid the warning in
the HTML, force the removal; if the volume does not exist, no warning is
emitted.
To still catch possible problems, do not do this in the `terminate.xml`
so we might still see if there are other problems.
Laurent noticed it on one of his MR and confirmed with him:
-- Volumes have be created the 1st time they ran on avra on July 7th
-- Volumes were created with not only the raw files but also the nr-softmodem executable
Solution: two-fold:
1. using the `docker-compose down -v` syntax, the volume is deleted automatically
2. I added redundancy with the custom command to remove the used volume
Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>