This has been banned since the introduction of Portal Type class. When creating
a new ERP5Form via addERP5Form/ZMI, its MRO:
  * Before:
    <class 'Products.ERP5Form.Form.ERP5Form'>
    <class 'Products.ERP5Type.Base.Base'>
    ...
    <type 'ExtensionClass.Base'>
  * Now:
    <class 'erp5.portal_type.ERP5 Form'>,
    <class 'Products.ERP5Form.Form.ERP5Form'>,
    <class 'Products.ERP5Type.Base.Base'>,
    ...
    <class 'erp5.accessor_holder.property_sheet.SimpleItem'>
    <class 'erp5.accessor_holder.property_sheet.Folder'>
    <class 'erp5.accessor_holder.property_sheet.Base'>
    <class 'erp5.accessor_holder.property_sheet.CategoryCore'>
    <class 'erp5.accessor_holder.BaseAccessorHolder'>
    <class 'Products.ERP5Type.dynamic.portal_type_class.GetAcquireLocalRolesMixIn'>
    <type 'ExtensionClass.Base'>

Thus it was missing many accessors and was working only by chance (or at least
unless these accessors were not called until the object was automatically migrated
by the next call to __setstate__). Namely, as `providesI*` accessors are now in
BaseAccessorHolder rather than Base due to ZODB Components, this breaks reindexing
(`AttributeError: providesIPredicate`).

Also, remove hardcoded _getAcquireLocalRoles() now that it is not used as a regular
class anymore. Set this on the portal type object instead.