Bug#1058968: python-graphviz: please remove obsolete extraneous Build-Dep on python3-unittest2

[Alexandre Detiste]

Source: python-graphviz
Severity: normal

Dear Maintainer,

python3-unittest2 was a backport of Python3's "unittest" to Python2.

Upstream has switched to use the real thing.

Can you please remove the references in:

  d/control
  d/test/control

Greetings