Ceph » rbd

I found it became necessary to rework a little of the rbd code
while working through having the osd support multiple data items.

The rbd code has always used only one op per request, and
a while ago I made that obvious in the code as well. But
the time has come where some things were done with that
assumption in mind that won't work right for multiple ops.

This isn't a big deal, I just wanted to report it separately.