Merge 1487796 from trunk:

* network_io/unix/multicast.c (do_mcast_opt): Fix regression in
  handling IPv4 options introduced in r1309386.



git-svn-id: https://svn.apache.org/repos/asf/apr/apr/branches/1.2.x@1487801 13f79535-47bb-0310-9956-ffa450edef68