tests/test-revlog-packentry.t

parsers: fix width of datalen variable in fm1readmarkers

Because parsers.c does not define PY_SSIZE_T_CLEAN, "s#" format requires
(const char*, int), not (const char*, Py_ssize_t).

https://docs.python.org/2/c-api/arg.html

This error had no problem before 042344313939, where datalen wasn't used.
But now fm1readmarkers() fails with "overflow in obsstore" on Python 2.6.9
(amd64) because upper bits of datalen seem to be filled with 1, making it
a negative integer.

This problem seems not visible on our Python 2.7 environment because upper
bits happen to be filled with 0.

  $ 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 ..