+++ This bug was initially created as a clone of Bug #647386 +++ This is basically the complementary of having live snapshots, but is also needed regardless. The ability required is to delete a qcow2 snapshot from an active chain. Note that in case of crash / failure, the chain and any subset of it have to remain in a stable and consistent state.
oVirt 3.5 has been released and should include the fix for this issue.