ir.values: remove excess indices, limits. Cleanup
ir.values: remove excess indices, limits. Cleanup

Having too many overlapping indices may actually slow postgres down. Also,
the [:200] limitation is not valid, since key2 is varchar(128) anyway.

Note that ir.values may need an overhaul, wrt. defaults, because their
functionality is poor at the moment.

xrg/openerp-server,xrg/openerp-server