[IMP] Give precedence to module directories instead of zips while locating resources

[IMP] Give precedence to module directories instead of zips while locating resources

The previous behavior gave the precedence to zipped
modules, without any apparent reason, and this is
sub-optimal for several reasons:

1. The default is to have regular modules, not
zipped modules, so looking first for a regular
module is more efficient.
2. Keeping a zipped module next to a regular
module with the same name is not a documented
or supported feature.
3. Even if you were relying on this behavior
having the extracted module take precedence
is more practical: you could simply extract
the zipped module to test a quick fix.

We have another issue related to this feature
because the code looking for zipped modules
escapes the addons paths chroot and goes
up to the filesystem root looking for a zip
module at each step. This is described in
bug 928376 and a fix for it should follow.

lp bug: https://launchpad.net/bugs/928376 fixed

bzr revid: odo@openerp.com-20120208173932-pwhz53vxxdzbo8ja