evolve: store the old other divergent node after relocation in evolvestate
When the content-divergent changes are on different parents and we relocate of
the node to the parent of another one, we get a new other-divergent node. We
still need to store the older other-divergent in evolvestate so that we can use
that information.
#require test-repo pyflakes
Copied from Mercurial core (60ee2593a270)
$ cd "`dirname "$TESTDIR"`"
run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)
$ hg locate 'set:(**.py or grep("^#!.*python")) - removed()' 2>/dev/null \
> | xargs pyflakes 2>/dev/null