Backport handoff_ip bug fix from pull request #176 from master to 1.1. Master commit: fae63a8 Change handoff_sender to respect the custom handoff_ip setting configured on the handoff target node. Prior to this change, the listener would bind to the configured IP address, but the sender would attempt to connect to the default IP address associated with the node name. Thanks go to @micmac for providing the initial version of this patch.
Fix potential badmatch from re-using variable TNHandoffIP. Change get_handoff_ip to use standard try/catch block, and default to using the normal hostname if unable to resolve the handoff IP.
Ensures vnodes responsible for fallback data are eventually started. Resolves issue #154
Resolve issue #155
Resolve issue #144. Change riak_core_vnode_master to still handle return_vnode messages given that pre-1.1 nodes may still send those messages to a 1.1 node. Add legacy routing logic to riak_core_vnode_master:command_return_vnode in order to properly send messages to pre-1.0 nodes that do not have vnode proxy processes.
Allowing duplicates was breaking the pipe and kv unit tests.