Merge r1567221 from trunk:

mod_lua: Fix r:setcookie() to add, rather than replace,
the Set-Cookie header. PR56105

Submitted By: Kevin J Walters <kjw ms com>, Edward Lu <Chaosed0 gmail com>
Committed By: covener




git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1567328 13f79535-47bb-0310-9956-ffa450edef68