storage/reflink: show size in refused volume shrink message
storage/reflink: show size in refused volume shrink message

Like e6bb282 did for lvm.

marmarek/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,QubesOS/qubes-core-admin