evolve: use stack template in --continue case also
We use stack indexes (s#) in evolve msging when revs being evolved are
in active topic. Before this patch we are not covering the --continue case.
So this patch cover the same and use the stack indexes s# even when we
continue an interrupted evolve.
In this patch I used the same concept (to check if we should use s#)
as we are using in cases other than `--continue`. Thanks to PYD for
refactoring those lines.
Changes in tests also reflects the expected behaviour.
