Conflicts:
	component/firefox/buildout.cfg

This reverts commit 781c1a44.
Extended .cfg files are not cooperating, so += is unusable in [buildout]
section, even for find-links.

Conflicts:
	stack/erp5/buildout.cfg
(cherry picked from commit b4085e58)

This reverts commit 781c1a44.
Extended .cfg files are not cooperating, so += is unusable in [buildout]
section, even for find-links.

Conflicts:
	stack/erp5/buildout.cfg

also pin 'cloudooo = 1.2.5-dev' to avoid possible usage of old released 1.2.3 egg.

Also, simplify syntax (no need for a loop).
Also, actually propagate error from all commands.