[Checkins] [zopefoundation/BTrees] e77927: sync split rule with C code.

[GitHub]

  Branch: refs/heads/node-sizes
  Home:   https://github.com/zopefoundation/BTrees
  Commit: e779278d946750c56dea912de3b4ab47048ef359
      https://github.com/zopefoundation/BTrees/commit/e779278d946750c56dea912de3b4ab47048ef359
  Author: Jim Fulton <jim at zope.com>
  Date:   2014-05-25 (Sun, 25 May 2014)

  Changed paths:
    M BTrees/_base.py

  Log Message:
  -----------
  sync split rule with C code.