testing/openvswitch: fix creation/upgrade of database

Instead of create/update database from install script we do it from
init.d script. This is becase:

 - we need /dev/urandom, which might not exist til until the mdev/udev
   service is started. We cannot assume those are running during
   install

 - in case of upgrade, if the service is running (which is normally is)
   we will get locking error because the db is in use.

We solve both those things by creating/upgrading the database before
starting it, from the init.d script.

fixes #3417