expression: fix "m2o, m2m in []" expressions, bug 626806
expression: fix "m2o, m2m in []" expressions, bug 626806

After some discussions, we decided that the desired behavior of the
ORM for one2many and many2many fields should be:
 (foobar_id,'in', []) => empty result, because the list is empty
 (foobar_id,'in',False) => find records that don't have a foobar

vnc-biz/openerp-server,MarkusTeufelberger/openobject-server,MarkusTeufelberger/openobject-server,gisce/openobject-server,gisce/openobject-server,splbio/openobject-server,splbio/openobject-server,ovnicraft/openerp-server,gisce/openobject-server,vnc-biz/openerp-server,ovnicraft/openerp-server,MarkusTeufelberger/openobject-server,splbio/openobject-server