HTTPCLIENT-1353: 303 redirects should be cacheable
Patch contributed by James Leigh <james at 3roundstones dot com>. This
change allows the async client to use a new CacheConfig option to allow
for this caching. Please see the following for details:
https://issues.apache.org/jira/browse/HTTPCLIENT-1353


git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpasyncclient/trunk@1491497 13f79535-47bb-0310-9956-ffa450edef68