hg: jdk/submit: 8222562: Don't set IPV6_V6ONLY when IPv4 is not available

[jianglizhou at google.com]

Changeset: 22323f20401b
Author:    aeubanks
Date:      2019-04-16 13:16 -0700
URL:       http://hg.openjdk.java.net/jdk/submit/rev/22323f20401b

8222562: Don't set IPV6_V6ONLY when IPv4 is not available
Reviewed-by: dfuchs, chegar
Contributed-by: aeubanks at google.com

! src/java.base/share/native/libnet/net_util.c
! src/java.base/share/native/libnet/net_util.h
! src/java.base/unix/native/libnet/PlainDatagramSocketImpl.c
! src/java.base/unix/native/libnet/PlainSocketImpl.c
! src/java.base/unix/native/libnet/net_util_md.c
! src/java.base/unix/native/libnio/ch/Net.c
! src/java.base/windows/native/libnet/net_util_md.c