Re-model the job auth

We have decided to rename the 'password' auth to 'secrets' on the
zuulv3 spec.
The idea is that we will both encrypt the user and password using
PKCS1, also allowing to have more than one secrets.
This change modifies the model to meet new spec requirements.

Change-Id: Ief78ac27732f30b17d7995a3e2032e33e7979ca9
diff --git a/tests/test_model.py b/tests/test_model.py
index fa670a4..0d4c7b6 100644
--- a/tests/test_model.py
+++ b/tests/test_model.py
@@ -136,9 +136,9 @@
             'parent': 'base',
             'timeout': 40,
             'auth': {
-                'password': {
-                    'pypipassword': 'dummypassword'
-                }
+                'secrets': [
+                    'pypi-credentials',
+                ]
             }
         })
         layout.addJob(pypi_upload_without_inherit)
@@ -149,9 +149,9 @@
             'timeout': 40,
             'auth': {
                 'inherit': True,
-                'password': {
-                    'pypipassword': 'dummypassword'
-                }
+                'secrets': [
+                    'pypi-credentials',
+                ]
             }
         })
         layout.addJob(pypi_upload_with_inherit)
@@ -163,9 +163,9 @@
                 'timeout': 40,
                 'auth': {
                     'inherit': False,
-                    'password': {
-                        'pypipassword': 'dummypassword'
-                    }
+                    'secrets': [
+                        'pypi-credentials',
+                    ]
                 }
             })
         layout.addJob(pypi_upload_with_inherit_false)
@@ -190,9 +190,9 @@
         layout.addJob(in_repo_job_with_inherit_false)
 
         self.assertNotIn('auth', in_repo_job_without_inherit.auth)
-        self.assertIn('password', in_repo_job_with_inherit.auth)
-        self.assertEquals(in_repo_job_with_inherit.auth['password'],
-                          {'pypipassword': 'dummypassword'})
+        self.assertIn('secrets', in_repo_job_with_inherit.auth)
+        self.assertEquals(in_repo_job_with_inherit.auth['secrets'],
+                          ['pypi-credentials'])
         self.assertNotIn('auth', in_repo_job_with_inherit_false.auth)
 
     def test_job_inheritance_job_tree(self):