evolve: fix storage of replacements and temprevs node in evolvestate
The _completephaseivergent() was not respecting rules on how to store the new
node ids created in evolvestate. The rules are:
* store the temporary relocated commits in temprevs
* store the final new commit in replacements
This patch make sure we follow the above rules and also use the return value
returned by _resolvephasedivergence().
The tests change demonstrates that we are all good now.
extrakey = 'topic'
changekey = '_rewrite_noise'