Revert "Drop useless use of pifpaf"

This reverts commit b5d50d89.

This only worked because I have a local postgresql on which I'm superuser,
apparently.

tox.ini

@@ -4,26 +4,27 @@ envlist=flake8,black
 [testenv]
 basepython = python3
 passenv = SPHINXOPTS JAVA_HOME
-whitelist_externals = /usr/bin/make
 
 [testenv:sphinx]
 extras =
   building
 deps =
   django < 3
+  pifpaf
 setenv =
   SWHPKGDIR = {envsitepackagesdir}/swh
 commands =
-  make -C docs {posargs:html}
+  {envpython} -m pifpaf run postgresql -- make -C docs {posargs:html}
 
 [testenv:sphinx-dev]
 deps =
   django < 3
   -rrequirements-swh-dev.txt
+  pifpaf
 setenv =
   SWHPKGDIR = {envsitepackagesdir}/swh
 commands =
-  make -C docs {posargs:html}
+  {envpython} -m pifpaf run postgresql -- make -C docs {posargs:html}
 
 [testenv:black]
 skip_install = true