Reduce potential confusion with the global tools namespace. Will
hopefully make it possible to remove the annoying initial :: when
referring to the global tools namespace. Unless we have even more
tools subnamespaces somewhere.

Thorsten said it was OK.

Change-Id: Id088dfe8f4244cb79df9aa988995b31a1758c996
Reviewed-on: https://gerrit.libreoffice.org/42644Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tor Lillqvist <tml@collabora.com>