[FIX] openerp.modules.loading: previous change disabled demo data altogether,

[FIX] openerp.modules.loading: previous change disabled demo data altogether,
this should be now fixed by making sure that --withou-demo flag (or its absence)
is taken care of, and setting the base module demo field.
Normally the demo state of a module should have a ripple
effect on all modules depending on it. This might prove
not enough in this case and require some more testing.

bzr revid: vmt@openerp.com-20111117162824-yqswv6yk7bmiyj4s