Force password_encryption to md5 while SCRAM is unsupported.

Author: jwp

postgresql/test/test_connect.py

@@ -80,13 +80,19 @@ def configure_cluster(self):
 		if has_ipv6:
 			listen_addresses += ',::1'
 
+		if self.cluster.installation.version_info >= (10, 0):
+			pwe = 'md5'
+		else:
+			pwe = 'on'
+
 		self.cluster.settings.update(dict(
 			port = str(self.cluster_port),
 			max_connections = '6',
 			shared_buffers = '24',
 			listen_addresses = listen_addresses,
 			log_destination = 'stderr',
 			log_min_messages = 'FATAL',
+			password_encryption = pwe,
 		))
 
 		if self.disable_replication: