Create new releases for puppet-nova in train and ussuri

Some fixes have been added in puppet-nova since last releases. One of
them is needed for CentOS 8.2.

Also, a new parameter has been added so i'm bumping intermediate
release.

Change-Id: I7030bc9ffc6026935ef76d8481bd7fef5838e8a5

deliverables/train/puppet-nova.yaml

@@ -26,6 +26,10 @@ releases:
     projects:
       - repo: openstack/puppet-nova
         hash: 831c9ddc259b242e8ab209fa944cde2dfb39a598
+  - version: 15.6.0
+    projects:
+      - repo: openstack/puppet-nova
+        hash: 655027005c95b4146ab4e6cb5a70290a9e6881db
 branches:
   - name: stable/train
     location: 15.4.0

deliverables/ussuri/puppet-nova.yaml

@@ -26,6 +26,10 @@ releases:
       - hash: c3b2e2dc9e8aa4ab48dceb63f9295687bd18f295
         repo: openstack/puppet-nova
     version: 16.3.0
+  - projects:
+      - hash: 0d7f13ff9b60952cd19fee0ce40bf5ea007f2137
+        repo: openstack/puppet-nova
+    version: 16.4.0
 branches:
   - name: stable/ussuri
     location: 16.3.0