entrypoint: set default env var for requiring cephfs mount point
entrypoint: set default env var for requiring cephfs mount point

When running cephfs tests locally there is no strong urge to require
an environment exactly like that of the test container. However, we do
want tests run under the container image (especially our default ci) to
use the cephfs mountpoint as they were previously. Set a default value
in the entrypoint script to require the mountpoint so we don't
accidentally miss the tests if something unexpected goes wrong.

Signed-off-by: John Mulligan <eda8ad33169deab44f9fe65847f99e368da6c91b@redhat.com>

ceph/go-ceph,ceph/go-ceph,ceph/go-ceph