fix(ci): properly removing docker volumes

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>

ci-scripts/main.py

@@ -750,7 +750,6 @@ elif re.match('^TesteNB$', mode, re.IGNORECASE) or re.match('^TestUE$', mode, re
 				elif action == 'WaitEndBuild_eNB':
 					RAN.WaitBuildeNBisFinished(HTML)
 				elif action == 'Custom_Command':
-					logging.info(f"Executing custom command")
 					RAN.CustomCommand(HTML)
 					if RAN.prematureExit:
 						CiTestObj.AutoTerminateeNB(HTML,RAN,EPC,CONTAINERS)