We do not want to join pod namespaces if no infra container is
present. A pod may claim it shares namespaces without an infra
container (I'll take an action item to fix that - it really
should not be allowed), which was tripping up our default
namespace code and forcing us to try and join the namespaces of
the nonexistant infra container.
Signed-off-by: Matthew Heon <mheon@redhat.com>
b1552d9124