WIP: opencv: disable by default

Status Job ID Name Coverage
  External
passed cdash

failed ghostflow-branch-check-master

failed ghostflow-commit-check

failed smtk-kerbin-windows-shared-release+superbuild

failed smtk-praxis-windows-shared-release+superbuild

failed smtk-kerbin-windows-shared-release+superbuild

failed smtk-kerbin-windows-shared-release+superbuild

failed smtk-kerbin-windows-shared-release+superbuild

failed smtk-kerbin-windows-shared-release+superbuild

01:03:43

failed smtk-kerbin-windows-shared-release+superbuild

failed smtk-praxis-windows-shared-release+superbuild

00:19:57

failed smtk-praxis-windows-shared-release+superbuild

failed smtk-praxis-windows-shared-release+superbuild

failed smtk-praxis-windows-shared-release+superbuild

failed smtk-praxis-windows-shared-release+superbuild