Fix IPv6 multicast TTLs.

There's a Linux kernel bug we need to work-around for now. This patch adds that
workaround and tidies up the getSocketOption implementation.

This also fixes a bug I introduced in the last patch where setSocketOption
would reject InetAddress parameters.

Change-Id: Ie309b693520fed8306d346d5b4492c42e8967721
2 files changed