PYTHON-3725 Fix Test Failure - MockupDB test_network_disconnect_primary (#1222)

Author: DainisGorbunovs

doc/contributors.rst

@@ -95,3 +95,4 @@ The following is a list of people who have contributed to
 - Ben Warner (bcwarner)
 - Jean-Christophe Fillion-Robin (jcfr)
 - Sean Cheah (thalassemia)
+- Dainis Gorbunovs (DainisGorbunovs)

test/mockupdb/test_network_disconnect_primary.py

@@ -26,12 +26,12 @@ def test_network_disconnect_primary(self):
         # Application operation fails against primary. Test that topology
         # type changes from ReplicaSetWithPrimary to ReplicaSetNoPrimary.
         # http://bit.ly/1B5ttuL
-        primary, secondary = servers = (MockupDB() for _ in range(2))
-        for server in servers:
+        primary, secondary = MockupDB(), MockupDB()
+        for server in primary, secondary:
             server.run()
             self.addCleanup(server.stop)
 
-        hosts = [server.address_string for server in servers]
+        hosts = [server.address_string for server in (primary, secondary)]
         primary_response = OpReply(
             ismaster=True, setName="rs", hosts=hosts, minWireVersion=2, maxWireVersion=6
         )