rhg: Rename some revlog-related types and methods
Use "data chunck" and "data" for a revlog entry’s data before and after
resolving deltas (if any), repsectively.
The former `FilelogEntry` actually only contains data, rename it to
`FilelogRevisionData` accordingly. This leaves room to later have a
`FilelogEntry` type that wraps `RevlogEntry`.
Differential Revision: https://phab.mercurial-scm.org/D11959
$ hg init a
$ cd a
$ touch a; hg commit -qAm_
$ hg bookmark $(for i in $($TESTDIR/seq.py 0 20); do echo b$i; done)
$ hg clone . ../b -q
$ cd ../b
Checking that when lookup multiple bookmarks in one go, if one of them
fails (thus causing the sshpeer to be stopped), the errors from the
further lookups don't result in tracebacks.
$ hg pull -r b0 -r nosuchbookmark $(for i in $($TESTDIR/seq.py 1 20); do echo -r b$i; done) ssh://user@dummy/$(pwd)/../a
pulling from ssh://user@dummy/$TESTTMP/b/../a
abort: unknown revision 'nosuchbookmark'
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