lib/tests/zodb/zurl_2zstor/NEO: Test \w >1 master node

This patch amends the test for the function 'zurl_2zstor' by checking if
a NEO cluster with multiple master nodes can be converted. This must
work for real-world usage where NEO clusters with more than one master
node is used. Before this commit this test was missing.

lib/tests/test_zodb.py

@@ -525,6 +525,7 @@ def test_zstor_2zurl(tmpdir, neo_ssl_dict):
     _(neo("test",  "127.0.0.1:1234", 1),      "neos://%s@127.0.0.1:1234/test" % sslp) #   + ssl
     _(neo("test",  "[::1]:1234"),             "neo://[::1]:1234/test")                # NEO/ip6
     _(neo("test",  "[::1]:1234", 1),          "neos://%s@[::1]:1234/test" % sslp)     #   + ssl
+    _(neo("test",  "[::1]:1234\n[::2]:1234"), "neo://[::1]:1234,[::2]:1234/test")     #   + 2 master nodes
     _(demo(zeo("base", ("1.2.3.4",  5)),                                              # DemoStorage
            fs1("delta.fs")),                "demo:(zeo://1.2.3.4:5?storage=base)/(file://%s/delta.fs)" % tmpdir)