osdeps: replace RedHat-7.json with symlink
osdeps: replace RedHat-7.json with symlink

RedHat-7.json is currently identical to CentOS-7.json, replace with
symlink.

artefactual/archivematica-storage-service,artefactual/archivematica-storage-service,artefactual/archivematica-storage-service,artefactual/archivematica-storage-service