fix server version handling

Author: blink1073

doc/conf.py

@@ -105,7 +105,7 @@
 client = MongoClient()
 client.drop_database("doctest_test")
 db = client.doctest_test
-server_major_version = int(client.server_info()['version'].split()[0])
+server_major_version = int(client.server_info()['version'].split()[-1][0])
 """
 
 # -- Options for HTML output ---------------------------------------------------