IPv6 error on daemon startup

[jasonkgreen]

0.3.8-dev on Raspberry pi B+
ipfs daemon gives:

Initializing daemon...
ERRO[22:54:27:000] error from node construction: 1: listen tcp6 [::]:4001: socket: address family not supported by protocol
module=cmd/ipfs
Error: 1: listen tcp6 [::]:4001: socket: address family not supported by protocol

workaround: delete ipv6 line from swarm section of config file

[jbenet]

ideally this would not happen. ipfs init could check the OS stack and avoid adding the ip6 addr in that case.

[lidel]

Not listening on ipv6 anymore, dynamically enabling it is tracked in #5905