Remove yamllint from upper-constraints.txt
Remove yamllint from upper-constraints.txt

OpenStack doesn't list test requirements in upper constraints [1].

[́1] https://github.com/openstack/requirements/blob/stable/pike/upper-constraints.txt

Change-Id: I7472158d385beb311c159563bc3bb973c4a2d4c7
Signed-off-by: Cédric Ollivier <d48310251a4a484d041bc5d09a9ac4d86d20f793@orange.com>

opnfv/functest,mywulin/functest,opnfv/functest,mywulin/functest