Document whether it also works with OVH Cloud Archive

[alexanderkjeldaas]

OVH Cloud Archive lists this technology as an available protocol, but it doesn't seem to be a perfect fit with the architecture diagram on OVH's site.

Update the documentation to clarify that it does in fact work with OVH Cloud Archive (not only OVH Object Storage)

[xlucas]

Good point. Yes it does, but you have to be aware that:

• An attempt to retrieve a sealed object triggers its unsealing process.
• As long as an object is sealed, open(2) calls return EAGAIN (i.e. Resource temporarily unavailable).