**Description of the issue/feature this PR addresses:**
This commit had been submitted previously, #11846, but was closed due to some house keeping I had performed on my branch. It addresses the use of %d as a placeholder within the point_of_sale module's "pos_order_report" report and openerp/tests' common.py.

Per psycopg's documentation[1], "the variables placeholder must always be a %s, even if a different placeholder (such as a %d for integers or %f for floats) may look more appropriate."

[1] http://initd.org/psycopg/docs/usage.html#passing-parameters-to-sql-queries

See commit ed7567d, as well, which reads as follows:

[REM] sql_db: legacy useless tests and duplicate exception block

The test for %f/%d is useless, eveybody has been using %s for ages, and the psycopg2 error is pretty explicit if you don't.

**Current behavior before PR:**
The use of %d should lead to an error, according to both psycopg's documentation and @odony, but isn't. This behavior, however, has nothing to do with the sql_db test being removed in ed7567d as that test was still present on 9.0 when I checked.

**Desired behavior after PR is merged:**
Compliant type.

I confirm I have signed the CLA and read the PR guidelines at www.odoo.com/submit-pr
Cody Kitterman