Fix previous merge

A call to _CalculateGroupIPolicy wasn't refactored during the merge.

Signed-off-by: Bernardo Dal Seno <bdalseno@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

lib/cmdlib.py

@@ -10266,7 +10266,7 @@ class LUInstanceCreate(LogicalUnit):
       }
     group_info = self.cfg.GetNodeGroup(pnode.group)
-    ipolicy = _CalculateGroupIPolicy(cluster, group_info)
+    ipolicy = ganeti.masterd.instance.CalculateGroupIPolicy(cluster, group_info)
     res = _ComputeIPolicyInstanceSpecViolation(ipolicy, ispec)
     if not self.op.ignore_ipolicy and res:
       raise errors.OpPrereqError(("Instance allocation to group %s violates"