Add linaro-london to nodepool

This cloud should be ready to accept CI jobs.  The mirror is up and
working and the cloud launcher has applied against it.  The os.large
flavour is there, and there should be enough resources for 8 nodes.

Change-Id: I1cdd0245cb91ea11763cae6b6531045cde14e82f

nodepool/nl03.openstack.org.yaml

@@ -335,6 +335,39 @@ providers:
             diskimage: ubuntu-bionic-arm64
             key-name: infra-root-keys-2018-06-15
 
+  - name: linaro-london
+    region-name: 'London'
+    cloud: linaro-london
+    boot-timeout: 600
+    launch-timeout: 800
+    rate: 0.001
+    diskimages:
+      - name: debian-stretch-arm64
+        config-drive: true
+      - name: ubuntu-xenial-arm64
+        config-drive: true
+      - name: ubuntu-bionic-arm64
+        config-drive: true
+    pools:
+      - name: main
+        max-servers: 8
+        labels:
+          - name: debian-stretch-arm64
+            min-ram: 8000
+            flavor-name: 'os.large'
+            diskimage: debian-stretch-arm64
+            key-name: infra-root-keys-2018-06-15
+          - name: ubuntu-xenial-arm64
+            min-ram: 8000
+            flavor-name: 'os.large'
+            diskimage: ubuntu-xenial-arm64
+            key-name: infra-root-keys-2018-06-15
+          - name: ubuntu-bionic-arm64
+            min-ram: 8000
+            flavor-name: 'os.large'
+            diskimage: ubuntu-bionic-arm64
+            key-name: infra-root-keys-2018-06-15
+
 diskimages:
   - name: centos-7
   - name: debian-stretch