FIX: only run migration on DB's migrating from v6.1

[JosDeGraeve]

Upgrading from v7.0 to v8.0 fails because the table account_voucher_sale_order_rel does not exist.
The v8.0 db was migrated by odoo from v7 -> v8

producing this stack trace:

2016-03-17 17:45:35,174 14774 INFO mooddesign8 openerp.modules.migration: module sale_payment_method: Running migration [0.1>] sale.order:: V7 change/rename the field payment_id into amany2many with the name payment_ids
2016-03-17 17:45:35,174 14774 ERROR mooddesign8 openerp.sql_db: Programming error: relation "account_voucher_sale_order_rel" does not exist
LINE 1: INSERT INTO account_voucher_sale_order_rel(sale_order_id, ac...
                    ^
, in query INSERT INTO account_voucher_sale_order_rel(sale_order_id, account_voucher_id) (SELECT id, payment_id FROM  sale_order WHERE payment_id IS NOT NULL )
2016-03-17 17:45:35,174 14774 CRITICAL mooddesign8 openerp.service.server: Failed to initialize database `mooddesign8`.
Traceback (most recent call last):
  File "/opt/odoo/8.0/odoo/openerp/service/server.py", line 929, in preload_registries
    registry = RegistryManager.new(dbname, update_module=update_module)
  File "/opt/odoo/8.0/odoo/openerp/modules/registry.py", line 370, in new
    openerp.modules.load_modules(registry._db, force_demo, status, update_module)
  File "/opt/odoo/8.0/odoo/openerp/modules/loading.py", line 351, in load_modules
    force, status, report, loaded_modules, update_module)
  File "/opt/odoo/8.0/odoo/openerp/modules/loading.py", line 255, in load_marked_modules
    loaded, processed = load_module_graph(cr, graph, progressdict, report=report, skip_modules=loaded_modules, perform_checks=perform_checks)
  File "/opt/odoo/8.0/odoo/openerp/modules/loading.py", line 183, in load_module_graph
    migrations.migrate_module(package, 'post')
  File "/opt/odoo/8.0/odoo/openerp/modules/migration.py", line 171, in migrate_module
    migrate(self.cr, pkg.installed_version)
  File "/opt/odoo/8.0/addons-enabled/sale_payment_method/migrations/0.1/post-migration.py", line 32, in migrate
    cr.execute("INSERT INTO account_voucher_sale_order_rel"
  File "/opt/odoo/8.0/odoo/openerp/sql_db.py", line 158, in wrapper
    return f(self, *args, **kwargs)
  File "/opt/odoo/8.0/odoo/openerp/sql_db.py", line 234, in execute
    res = self._obj.execute(query, params)
ProgrammingError: relation "account_voucher_sale_order_rel" does not exist
LINE 1: INSERT INTO account_voucher_sale_order_rel(sale_order_id, ac...
                    ^

[pedrobaeza]

If this script is also present on 7.0 branch, here you should remove it, as you mustn't put the script in 2 major versions

[StefanRijnhart]

Agreed with @pedrobaeza, you can remove the script in the 8.0 branch.

[coveralls]

Coverage decreased (-0.03%) to 73.832% when pulling d6957f6 on apertoso:8.0-fix_postmigration into e439f5c on OCA:8.0.

[pedrobaeza]

👍

[n1b0r]

👍 The post-migration script break the migration process from 7.0 to 8.0. This PR resolve the issue