Freeze sqlalchemy to 1.3 until problems with 1.4 are solved

Author: chaen

construct.yaml

@@ -42,7 +42,8 @@ specs:
   - mysql-client
   # Earlier versions of mysqlclient were build with older MySQL versions
   - mysqlclient >=2.0.3
-  - sqlalchemy >=1.0.9
+  # Freeze until all problems with 1.4 are solved
+  - sqlalchemy ==1.3.*
   - stomp.py =4.1.23
   # Middleware
   - apache-libcloud