Add building of openSUSE Tumbleweed nodepool images

This is useful for experimental devstack runs that allow testing
e.g. Nova or Neutron against the newest technology as it gets
into the rolling release of openSUSE Tumbleweed (like for
example testing latest OVS, kernel and other OS dependencies).

Depends-On: https://review.openstack.org/545314/
Change-Id: Ied661ad453e6345956d466f15f728ce019affe3e

nodepool/nodepool.yaml

@@ -47,6 +47,8 @@ providers:
         config-drive: true
       - name: opensuse-423
         config-drive: true
+      - name: opensuse-tumbleweed
+        config-drive: true
       - name: ubuntu-trusty
         config-drive: true
       - name: ubuntu-xenial
@@ -199,6 +201,23 @@ diskimages:
       DIB_IMAGE_CACHE: /opt/dib_cache
       QEMU_IMG_OPTIONS: compat=0.10
       DIB_GRUB_TIMEOUT: '0'
+  - name: opensuse-tumbleweed
+    elements:
+      - opensuse-minimal
+      - vm
+      - simple-init
+      - openstack-repos
+      - nodepool-base
+      - cache-devstack
+      - growroot
+      - infra-package-needs
+    release: 'tumbleweed'
+    env-vars:
+      TMPDIR: /opt/dib_tmp
+      DIB_CHECKSUM: '1'
+      DIB_IMAGE_CACHE: /opt/dib_cache
+      QEMU_IMG_OPTIONS: compat=0.10
+      DIB_GRUB_TIMEOUT: '0'
   - name: ubuntu-trusty
     elements:
       - ubuntu-minimal