High: PE: Fix manditory ordering with m/s resources
We had a problem if a resource requires a m/s resource to be demoted before it
can stop and the instance was only a slave. In such cases we couldn't stop the
resource (and move it).
This was shown up by changing the default for rsc_order.score to INFINITY.

Mercurial revision: 1aef353d7d6318c862b86c314fa314cd2c7b84c9