This reverts commit ae808179.

Reason for revert: zodbtools depend on ZODB while currently neoppod &
erp5 are depending on `ZODB3 = 3.10` so upon installing both ZODB3 and
ZODB are installed. Together with our requirement

    stack/erp5/zope-versions.cfg:transaction = 1.1.1

This creates version conflict and installation fails:

2016-11-17 14:56:35,858 testsuite    : INFO     slapgrid_sr : 2016-11-17 14:56:35 slapos[3698] INFO The version, 1.1.1, is not consistent with the requirement, 'transaction>=1.6.1'.
2016-11-17 14:56:35,937 testsuite    : INFO     slapgrid_sr : 2016-11-17 14:56:35 slapos[3698] INFO While:
2016-11-17 14:56:35,937 testsuite    : INFO     slapgrid_sr : 2016-11-17 14:56:35 slapos[3698] INFO   Installing neoppod.
2016-11-17 14:56:35,937 testsuite    : INFO     slapgrid_sr : 2016-11-17 14:56:35 slapos[3698] INFO Error: Bad version 1.1.1

So revert zodbtools hooking for now until we upgrade our ZODB to ZODB > 3.