tests/test-revlog-packentry.t

sparse: treat paths as cwd-relative

This commit makes it so sparse treats passed paths as CWD-relative,
not repo-root-realive. This is a more intuitive behavior in my (and some
other FB people's) opinion.

This is breaking change however. My hope here is that since sparse is
experimental, it's ok to introduce BCs.

The reason (glob)s are needed in the test is this: in these two cases we
do not supply path together with slashes, but `os.path.join` adds them, which
means that under Windows they can be backslashes. To demonstrate this behavior,
one could remove the (glob)s and run `./run-tests.py test-sparse.t` from
MinGW's terminal on Windows.

  $ hg init repo
  $ cd repo

  $ touch foo
  $ hg ci -Am 'add foo'
  adding foo

  $ hg up -C null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

this should be stored as a delta against rev 0

  $ echo foo bar baz > foo
  $ hg ci -Am 'add foo again'
  adding foo
  created new head

  $ hg debugindex foo
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       0  .....       0 b80de5d13875 000000000000 000000000000 (re)
       1         0      13  .....       1 0376abec49b8 000000000000 000000000000 (re)

  $ cd ..