[ZODB4] setup: tests_require += zope.testrunner

Zope.testrunner is used to run ZODB tests (see e.g. tox.ini). It was
specified as explicit dependency in tox.ini->deps and in buildout.cfg.
However if in SlapOS we install just ZODB[test] zope.testrunner won't be
installed.

-> Fix is by moving zope.testrunner dependency into setup, so that
ZODB[test] installs it. This is the same as what ZODB5 does:

https://github.com/zopefoundation/ZODB/blob/5.6.0-14-g0eae10cd0/setup.py#L48

setup.py

@@ -115,7 +115,7 @@ long_description = str(
      read_file("README.rst").decode('latin-1')  + "\n\n" +
      read_file("CHANGES.rst").decode('latin-1')))
 
-tests_require = ['zope.testing', 'manuel']
+tests_require = ['zope.testing', 'manuel', 'zope.testrunner >= 4.4.6']
 
 setup(name="ZODB",
       version=version,

tox.ini

@@ -12,9 +12,7 @@ commands =
     zope-testrunner -f --test-path=src --auto-color --auto-progress
 # without explicit deps, setup.py test will download a bunch of eggs into $PWD
 deps =
-    manuel
-    zope.testing
-    zope.testrunner >= 4.4.6
+    .[test]
 
 [testenv:simple]
 # Test that 'setup.py test' works