Use node UUIDs for locking instead of node names

LUInstanceMultiAlloc used node names instead of node UUIDs to lock
required nodes. This patch fixes this bug.
Signed-off-by: Thomas Thrainer <thomasth@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

lib/cmdlib/instance.py

@@ -1896,11 +1896,11 @@ class LUInstanceMultiAlloc(NoHooksLU):
       for inst in self.op.instances:
         (inst.pnode_uuid, inst.pnode) = \
           ExpandNodeUuidAndName(self.cfg, inst.pnode_uuid, inst.pnode)
-        nodeslist.append(inst.pnode)
+        nodeslist.append(inst.pnode_uuid)
         if inst.snode is not None:
           (inst.snode_uuid, inst.snode) = \
             ExpandNodeUuidAndName(self.cfg, inst.snode_uuid, inst.snode)
-          nodeslist.append(inst.snode)
+          nodeslist.append(inst.snode_uuid)
 
       self.needed_locks[locking.LEVEL_NODE] = nodeslist
       # Lock resources of instance's primary and secondary nodes (copy to