change compute.max_microversion in tempest.conf

Change-Id: I2092be9a712c6194d3ec585a7c9a990e83fdee17
diff --git a/tcp_tests/managers/runtestmanager.py b/tcp_tests/managers/runtestmanager.py
index 6c1e874..36ce174 100644
--- a/tcp_tests/managers/runtestmanager.py
+++ b/tcp_tests/managers/runtestmanager.py
@@ -303,6 +303,26 @@
                         " state.sls runtest.barbican_sign_image")},
             )
 
+        if self.image_version == 'mitaka':
+            commands.append({
+                'description': "Change max microversion",
+                'node_name': self.target_name,
+                'cmd': (
+                    "sed -i "
+                    "'s/max_microversion = 2.42/max_microversion = 2.25/' "
+                    " /tmp/test/tempest.conf")},
+            )
+
+        if self.image_version == 'newton':
+            commands.append({
+                'description': "Change max microversion",
+                'node_name': self.target_name,
+                'cmd': (
+                    "sed -i "
+                    "'s/max_microversion = 2.42/max_microversion = 2.38/' "
+                    "/tmp/test/tempest.conf")},
+            )
+
         self.__salt_api.execute_commands(commands=commands,
                                          label="Prepare for Tempest")