tests/test-extra-filelog-entry.t

repoview: flag `server.view` as experimental

Ideally, the non-experimental version of `experimental.extra-filter-revs` will
cover the use case for `server.view=immutable` well enough than having to have
this dedicated configuration. Since `server.view` is not part of any release, I
would prefer to have it marked as experimental to avoid having it to support it
for ever.

Issue351: mq: qrefresh can create extra revlog entry

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init
  $ hg qinit

  $ echo b > b
  $ hg ci -A -m foo
  adding b

  $ echo cc > b
  $ hg qnew -f foo.diff
  $ echo b > b
  $ hg qrefresh

  $ hg debugindex b
     rev linkrev nodeid       p1           p2
       0       0 1e88685f5dde 000000000000 000000000000