rebase: move state serialization to use unfiltered repo
Now that rebasestate is serialized as part of the transaction, the repo state it
sees is the version at the end of the transaction, which may have hidden nodes.
Therefore, it's possible parts of the rebase commit set are no longer visible by
the time the transaction is closing, which causes a filtered revision error in
this code. I don't think state serialization should be blocked from accessing
commits it knows exist, especially if all it's trying to do is get the hex of
them, so let's use an unfiltered repo here.
Unfortunately, the only known repro is with the fbamend Facebook extension, so
I'm not sure how to repro it in core Mercurial for a test.
running: init test1
result: None
running: add foo
result: 0
running: commit -m commit1 -d 2000-01-01 foo
result: None
running: commit -m commit2 -d 2000-01-02 foo
result: None
running: log -r 0
changeset: 0:0e4634943879
user: test
date: Sat Jan 01 00:00:00 2000 +0000
summary: commit1
result: None
running: log -r tip
changeset: 1:45589e459b2e
tag: tip
user: test
date: Sun Jan 02 00:00:00 2000 +0000
summary: commit2
result: None