[autotest] Remove synch_id from database

BUG=chromium:687781
TEST=Run migrate.py sync back and forth

Change-Id: Ib066b19d90b18ae9926e8aec2c871b963e6a2465
Reviewed-on: https://chromium-review.googlesource.com/441107
Commit-Ready: Allen Li <ayatane@chromium.org>
Tested-by: Allen Li <ayatane@chromium.org>
Reviewed-by: Dan Shi <dshi@google.com>
diff --git a/frontend/afe/doctests/001_rpc_test.txt b/frontend/afe/doctests/001_rpc_test.txt
index 89e29d6..c944353 100644
--- a/frontend/afe/doctests/001_rpc_test.txt
+++ b/frontend/afe/doctests/001_rpc_test.txt
@@ -109,7 +109,6 @@
 >>> data == [{'id': 1,
 ...           'hostname': 'ipaj1',
 ...           'locked': 1,
-...           'synch_id': None,
 ...           'status': 'Ready',
 ...           'labels': [],
 ...           'atomic_group': None,
@@ -470,7 +469,6 @@
 ...           'invalid': 0,
 ...           'locked': 0,
 ...           'status': 'Ready',
-...           'synch_id': None,
 ...           'protection': 'No protection',
 ...           'locked_by': None,
 ...           'lock_time': None,
diff --git a/frontend/afe/models_test.py b/frontend/afe/models_test.py
index a4eabfd..f0cf5ab 100755
--- a/frontend/afe/models_test.py
+++ b/frontend/afe/models_test.py
@@ -1,13 +1,14 @@
 #!/usr/bin/python
 
-import datetime
 import unittest
+
 import common
+from autotest_lib.client.common_lib import control_data
+from autotest_lib.client.common_lib import global_config
 from autotest_lib.frontend import setup_django_environment
 from autotest_lib.frontend.afe import frontend_test_utils
-from autotest_lib.frontend.afe import models, model_attributes, model_logic
-from autotest_lib.client.common_lib import global_config
-from autotest_lib.client.common_lib import control_data
+from autotest_lib.frontend.afe import model_logic
+from autotest_lib.frontend.afe import models
 
 
 class AclGroupTest(unittest.TestCase,
@@ -446,8 +447,7 @@
                            'locked': False,
                            'protection': 0,
                            'shard': {'hostname': '1', 'id': 1},
-                           'status': 'Ready',
-                           'synch_id': None}],
+                           'status': 'Ready'}],
                 'jobs': [{'control_file': 'some control file\n\n\n',
                           'control_type': 2,
                           'created_on': '2014-09-04T13:09:35',
diff --git a/frontend/afe/rdb_model_extensions.py b/frontend/afe/rdb_model_extensions.py
index 12ba892..4444122 100644
--- a/frontend/afe/rdb_model_extensions.py
+++ b/frontend/afe/rdb_model_extensions.py
@@ -184,9 +184,6 @@
     hostname = dbmodels.CharField(max_length=255, unique=True)
     locked = dbmodels.BooleanField(default=False)
     leased = dbmodels.BooleanField(default=True)
-    # TODO(ayatane): This is needed until synch_id is removed from Host._fields
-    synch_id = dbmodels.IntegerField(blank=True, null=True,
-                                     editable=settings.FULL_ADMIN)
     status = dbmodels.CharField(max_length=255, default=Status.READY,
                                 choices=Status.choices(),
                                 editable=settings.FULL_ADMIN)