Don't set parent_name in One2Many values

issue3900
review9311003
(grafted from 3139a1b5ce798e172d55c50597f4dc293f5618d8)

--HG--
branch : 2.6
extra : source : 3139a1b5ce798e172d55c50597f4dc293f5618d8
Fix wrong parent field name in EvalEnvionment
(grafted from 48e261835ea6a21fa6d1e4bc7e8590548a9a99e6)

--HG--
branch : 2.6
extra : source : 48e261835ea6a21fa6d1e4bc7e8590548a9a99e6
_parent_name and _parent_field_name must always be strings
(grafted from 02f3e38292d4e35d8f00a3567a8961fa782542f0)

--HG--
branch : 2.6
extra : source : 02f3e38292d4e35d8f00a3567a8961fa782542f0