[FIX] Can not execute line when stop date is EARLIER than current date
[FIX] migration: test if package is installed using its state.

checking if there is an installed version set is not enough because this field is not reset when the module is uninstalled
Merge pull request #2955 from odoo-dev/8.0-wmsmrpdatefix-jco

[FIX] Can not execute line when stop date is EARLIER than current date
[FIX] ir_actions: ids of unlink method can either be an ID list or one ID