Fixes #5692: Update send_clean.sh to meet quality standards

Ticket: http://www.rudder-project.org/redmine/issues/5692

To be merged in 3.0
I'm pretty sure we don't want to output stuff from this script when it's just doing it's job. It will just fill up logs.

I see two options:
1) We just remove any non error messages.
2) We add a "-v" option to make the script verbose, to help in debugging, and condition these "INFO" messages on that flag

Your choice.