[lyon] Set non-default cluster priority for orion and hercule

data/grid5000/sites/lyon/clusters/hercule/hercule.json

 {
   "created_at": "Tue, 02 Oct 2012 12:00:00 GMT",
+  "priority": "201299",
   "kavlan": true,
   "model": "Dell C6220",
   "production": true,

data/grid5000/sites/lyon/clusters/orion/orion.json

 {
   "created_at": "Fri, 14 Sep 2012 12:00:00 GMT",
+  "priority": "201299",
   "kavlan": true,
   "model": "Dell R720",
   "production": true,