Move creating server group from resource_setup to setUp

After microversion 2.13 'project_id' and 'user_id' are added to
the body of server group, but in resource_setup microversion is
not used, so server group created in resource_setup doesn't contain
'project_id' and 'user_id', which will cause MismatchError:
MismatchError: !=:
reference = {u'id': u'09b0b4e0-d886-4bb9-9193-6faab4f0cbc8',
 u'members': [],
 u'metadata': {},
 u'name': u'tempest-ServerGroupTestJSON-Server-Group-1629494857',
 u'policies': [u'affinity']}
actual = {u'id': u'09b0b4e0-d886-4bb9-9193-6faab4f0cbc8',
 u'members': [],
 u'metadata': {},
 u'name': u'tempest-ServerGroupTestJSON-Server-Group-1629494857',
 u'policies': [u'affinity'],
 u'project_id': u'8f3f6b0bd14047b68d267d58909c8f43',
 u'user_id': u'fb05421f04cb46bd81873c4fc314ed7f'}

This is to move the creating of common server group from
resource_setup to setUp, so that microversion can be used.

Change-Id: I94c6b8276c413839cda019e5d702f26bf1acb110
Closes-Bug: #1783258
diff --git a/tempest/api/compute/servers/test_server_group.py b/tempest/api/compute/servers/test_server_group.py
index 5286c8f..1b7cb96 100644
--- a/tempest/api/compute/servers/test_server_group.py
+++ b/tempest/api/compute/servers/test_server_group.py
@@ -47,8 +47,16 @@
         super(ServerGroupTestJSON, cls).resource_setup()
         cls.policy = ['affinity']
 
-        cls.created_server_group = cls.create_test_server_group(
-            policy=cls.policy)
+    def setUp(self):
+        super(ServerGroupTestJSON, self).setUp()
+        # TODO(zhufl): After microversion 2.13 project_id and user_id are
+        # added to the body of server_group, and microversion is not used
+        # in resource_setup for now, so we should create server group in setUp
+        # in order to use the same microversion as in testcases till
+        # microversion support in resource_setup is fulfilled.
+        if not hasattr(self, 'created_server_group'):
+            self.__class__.created_server_group = \
+                self.create_test_server_group(policy=self.policy)
 
     def _create_server_group(self, name, policy):
         # create the test server-group with given policy