phases: do not exchange secret changesets
Any secret changesets will be excluded from pull and push. Phase data are
properly synchronized on pull and push if a changeset is seen as secret locally
but is non-secret remote side.
This patch does not handle the case of a changeset secret on remote but known
locally.
$ hg init
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls
a
unknown