[FIX] packaging: Backport of efe3746 to 8.0

[FIX] packaging: debian: update-python-module is no more

The command is not installed by default. It was available in the
python-support library which we didn't depend on and now this library
is no more in debian jessie/ubuntu xenial.

Backported for odoo#13302

debian/postinst

@@ -24,8 +24,6 @@ case "${1}" in
         chmod 0750 $ODOO_LOG_DIR
         # Data dir
         chown $ODOO_USER:$ODOO_GROUP $ODOO_DATA_DIR
-        # update-python-modules NOW otherwise invoke-rc.d openerp start will fail
-        update-python-modules
         ;;
     *)
         ;;