The bash -e shebang does not work on CentOS 7.

The script can now locate itself and set LOFAR20_DIR accordingly.
This allows for multiple installations in parallel.

- Replace the set +e/set -e with || true when loading the Tango DB.
- Explain why in the world I am starting dsconfig twice.

L2SS-218 Addressing the comment that this file could be sourced when ssh'ing into the computer and it would break ssh when printing something that is unexpected.

This allows make to return with a non-0 code which in turn does
not force Bash to exit.  This happens when the containers where
already down and/or the volumes cleaned up.