use aether prefix for management node playbook

Change-Id: I31e93d606fe2d8837740c328b8db8259d200ed0f
diff --git a/playbooks/aethermgmt-playbook.yml b/playbooks/aethermgmt-playbook.yml
index 305b0e3..39be1c4 100644
--- a/playbooks/aethermgmt-playbook.yml
+++ b/playbooks/aethermgmt-playbook.yml
@@ -1,7 +1,7 @@
 # Ansible playbook to configure an aether management nodes
 
 - name: Configure an aether management node
-  hosts: mgmt
+  hosts: aethermgmt
   become: true
   roles:
     - netprep