[feature] default lease creation on skylakes

Add an option to create haswell allocations, but default to skylake
nodes.

Skylakes are required for power management.

chi-lease.py

@@ -32,7 +32,10 @@ def do_create(argv):
     end_time = start_time + datetime.timedelta(hours=argv.length)
 
     # resource properties
-    props = ['=', '$node_type', 'compute_haswell']
+    if argv.haswell:
+        props = ['=', '$node_type', 'compute_haswell']
+    else:
+        props = ['=', '$node_type', 'compute_skylake']
     resources = {'min': node_count,
                  'max': node_count,
                  'resource_type': 'physical:host',
@@ -102,6 +105,9 @@ def main():
 
     # create a lease
     parser_create = subparsers.add_parser("create", help="Create a lease")
+    parser_create.add_argument("--haswell",
+                               help="Use haswell nodes instead of skylake",
+                               action='store_true')
     parser_create.add_argument("name", help="Lease name")
     parser_create.add_argument("size", help="Number of hosts to lease",
                                type=int)