Tests are kind of broken in ZODB-5.3.0. Fix setup code and disable one
especially problematic test.

diff -u ZODB-5.3.0/setup.py ZODB-5.3.0/setup.py
--- ZODB-5.3.0/setup.py	2017-08-30 14:55:10.000000000 +0200
+++ ZODB-5.3.0/setup.py	2017-10-29 11:34:17.277953730 +0100
@@ -85,7 +85,10 @@
                     mod = __import__(
                         _modname(dirpath, base, os.path.splitext(filename)[0]),
                         {}, {}, ['*'])
-                    _unittests_only(suite, mod.test_suite())
+                    try:
+                        _unittests_only(suite, mod.test_suite())
+                    except AttributeError:
+                        pass
         elif 'tests.py' in filenames:
             mod = __import__(_modname(dirpath, base, 'tests'), {}, {}, ['*'])
             _unittests_only(suite, mod.test_suite())
diff -u ZODB-5.3.0/src/ZODB/scripts/tests/test_repozo.py ZODB-5.3.0/src/ZODB/scripts/tests/test_repozo.py
--- ZODB-5.3.0/src/ZODB/scripts/tests/test_repozo.py	2017-08-30 14:55:10.000000000 +0200
+++ ZODB-5.3.0/src/ZODB/scripts/tests/test_repozo.py	2017-10-29 11:35:10.348240386 +0100
@@ -1184,7 +1184,4 @@
         #unittest.makeSuite(Test_do_backup),  #TODO
         unittest.makeSuite(Test_do_recover),
         unittest.makeSuite(Test_do_verify),
-        # N.B.:  this test take forever to run (~40sec on a fast laptop),
-        # *and* it is non-deterministic.
-        unittest.makeSuite(MonteCarloTests),
     ])