Record provider/region/az in /etc/nodepool

Write the provider, region, and az names into /etc/nodepool/provider
in a form that can be sourced by a shell script.  Potentially used
by a ready script.

Change-Id: I48933ddb89a4a89cb22e1cb005469833f91c1f66

nodepool/nodepool.py

@@ -514,6 +514,12 @@ class NodeLauncher(threading.Thread):
                 f = ftp.open('/etc/nodepool/id_rsa.pub', 'w')
                 f.write(public_key)
                 f.close()
+                f = ftp.open('/etc/nodepool/provider', 'w')
+                f.write('NODEPOOL_PROVIDER=%s\n' % self.provider.name)
+                f.write('NODEPOOL_REGION=%s\n' % (
+                    self.provider.region_name or '',))
+                f.write('NODEPOOL_AZ=%s\n' % (self.node.az or '',))
+                f.close()
 
                 ftp.close()
             except Exception:

tools/fake.yaml

@@ -29,15 +29,12 @@ labels:
 providers:
   - name: fake-provider
     keypair: 'if-present-use-this-keypair'
+    region-name: 'fake-region'
     username: 'fake'
     password: 'fake'
     auth-url: 'fake'
     project-id: 'fake'
     max-servers: 96
-    pool: 'fake'
-    networks:
-      - net-id: 'some-uuid'
-      - net-label: 'some-label'
     images:
       - name: nodepool-fake
         base-image: 'Fake Precise'