[cinder][os-brick] hold recheck for cinder and os-brick

Hi All, Due to legacy jobs migration to bionic, we're facing a gate failure in cinder's cinder-tempest-dsvm-lvm-lio-barbican job and os-brick's legacy-tempest-dsvm-full-lio-src-os-brick and os-brick-cinder-tempest-dsvm-lvm-lio-barbican jobs. A workaround is proposed[1] and soon will be merged. Kindly avoid any recheck in cinder and os-brick until then. [1] https://review.openstack.org/#/c/643130/