container: add label ceph=True back

Add a label used by cephadm internally that was always set by
ceph-container [1] back to the new containerfile. This should
prevent issues with cephadm shell command thinking official ceph images
are not official ceph images.

[1] https://github.com/ceph/ceph-container/blob/30dc8b9a55f70a40983fd2da6ac31e1b9e977143/src/__DOCKERFILE_TRACEABILITY_LABELS__#L5

Signed-off-by: John Mulligan <[email protected]>

Author: phlogistonjohn

container/Containerfile

@@ -36,6 +36,7 @@ LABEL org.opencontainers.image.authors="Ceph Release Team <ceph-maintainers@ceph
       org.opencontainers.image.documentation="https://docs.ceph.com/"
 
 LABEL \
+ceph=True \
 FROM_IMAGE=${FROM_IMAGE} \
 CEPH_REF=${CEPH_REF} \
 CEPH_SHA1=${CEPH_SHA1} \