fix ssh test

tests/test_backup.py

@@ -13,7 +13,8 @@ import imp
 os.chdir(os.path.dirname(__file__))
 
 def test_ssh(server):
-    return subprocess.getstatus('ssh %s ls /tmp' % server) == 0
+    status, out = subprocess.getstatusoutput('ssh %s ls /tmp' % server) 
+    return status == 0
 
 def test_last_backup_is_recent(server, client):
     path = '/backup/%s/current' % client