zope4: Fix pylint import-error on BTrees since the version was bumped from 4.5.1 to 4.11.3.

5 jobs for zope4py2 in 0 seconds (queued for 1 second)
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Zope4Py2

01:47:18

failed ERP5.UnitTest-Zope4Py2

01:27:31

passed ERP5.CodingStyleTest-Zope4Py2

01:38:04

canceled ERP5.UnitTest-Zope4Py2

00:08:29

failed ERP5.UnitTest-Zope4Py2

02:01:07