Fix mysql packages 5.6 update

Change-Id: Iadf9da03ca068ba92aea2cdc7ce92e8daeab5587
diff --git a/tcp_tests/tests/system/test_mcp_update.py b/tcp_tests/tests/system/test_mcp_update.py
index 20c3a3f..d9ab74b 100644
--- a/tcp_tests/tests/system/test_mcp_update.py
+++ b/tcp_tests/tests/system/test_mcp_update.py
@@ -387,7 +387,6 @@
         # ################### Fix for Mysql 5.7  ##############################
         show_step(2)
         if (update_mysql_to_version == '5.7'):
-            mysql_update_bool = "True"
             mysql_class = "cluster.{env_name}.openstack." \
                           "database.mysql_version"\
                 .format(env_name=settings.ENV_NAME)
@@ -444,7 +443,7 @@
             'OS_DIST_UPGRADE': 'true',
             'OS_UPGRADE': 'true',
         }
-        if mysql_update_bool:
+        if (update_mysql_to_version == '5.7'):
             job_parameters.update({'UPDATE_TO_MYSQL57': 'true'})
 
         job_result, job_description = dt.start_job_on_jenkins(