merge stable into bug26084
blank members_state before maybe_erase_aliases
thus reverting b01e5808866d

We are the only member left. So our usual alias erasure condition of
"acks = pubs" needs to go since otherwise erasure could be deferred
indefintely, waiting for acks to arrive that never will. Blanking the
members_state effectively sets acks = pubs for all aliases, thus
enabling their unconditional erasure.
merge bug26084 into stable