add rbd support to qemu-kvm

add rbd support to qemu-kvm

to build, we need librbd-dev

http://ceph.com/debian/pool/main/c/ceph/librbd-dev_0.47.2-1~bpo60+1_amd64.deb

new dependencies:
ceph-common: include rbd command line
librbd and librados2 : rados protocol librairies

http://ceph.com/debian/pool/main/c/ceph/ceph-common_0.47.2-1~bpo60+1_amd64.deb
http://ceph.com/debian/pool/main/c/ceph/librbd1_0.47.2-1~bpo60+1_amd64.deb
http://ceph.com/debian/pool/main/c/ceph/librados2_0.47.2-1~bpo60+1_amd64.deb

official squeeze repository is
deb http://ceph.com/debian/ squeeze main

but maybe can we add packages in proxmox repository ?

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>