[requirements][nova][neutron] updating sqlalchemy to 1.3.4

so, there are no requirements type reasons why we can't merge this now, but functional tests seem to be failing for nova/neutron (tempest). Would those teams be able to test?

https://review.opendev.org/651591 is the test patch (now updated for 1.3.4)

Some failures show up here as well.

http://logs.openstack.org/39/661539/1/check/tempest-full/b127828/testr_resul...