refactor: Move FDV1_POLLING_ENDPOINT into datasource_common

Share the FDv1 polling endpoint from the sans-I/O datasource_common module
(next to STREAM_ALL_PATH) so the sync and async feature requesters no longer
each define their own copy.

Author: jsonbailey

ldclient/impl/datasource/datasource_common.py

@@ -11,6 +11,7 @@
 from ldclient.versioned_data_kind import FEATURES, SEGMENTS
 
 STREAM_ALL_PATH = '/all'
+FDV1_POLLING_ENDPOINT = '/sdk/latest-all'
 
 ParsedPath = namedtuple('ParsedPath', ['kind', 'key'])
 

ldclient/impl/datasource/feature_requester.py

@@ -8,14 +8,12 @@
 
 import urllib3
 
+from ldclient.impl.datasource.datasource_common import FDV1_POLLING_ENDPOINT
 from ldclient.impl.http import _http_factory
 from ldclient.impl.util import _headers, log, throw_if_unsuccessful_response
 from ldclient.interfaces import FeatureRequester
 from ldclient.versioned_data_kind import FEATURES, SEGMENTS
 
-FDV1_POLLING_ENDPOINT = '/sdk/latest-all'
-
-
 CacheEntry = namedtuple('CacheEntry', ['data', 'etag'])