SConstruct: Don't warn about disabled unused libraries
SConstruct: Don't warn about disabled unused libraries

If we manually disable both imath and openexr, we shouldn't complain that
openexr is disabled because we lack imath.

omco/geode,omco/geode,mikest/geode,mikest/geode,omco/geode,omco/geode,mikest/geode,mikest/geode