Sort vhost names in Nginx vhosts test.

tests/test_nginx_vhosts.py

@@ -55,7 +55,9 @@ resolution_ignored = conf.get('TESTER_VHOST_RESOLUTION_IGNORED', '').split(',')
 found = False
 errors = 0
 warnings = 0
-for name in os.listdir(nginx_dir):
+names = os.listdir(nginx_dir)
+names.sort()
+for name in names:
     path = os.path.join(nginx_dir, name)
     with open(path, 'r') as fo:
         vhost = fo.read()