fix raspberry pi arch ZMQError: Address family not supported by protocol

Raspberry Pi Test Image : ArchLinuxARM-2014.06-rpi.img

Before PR

```
# uname -a
Linux alarmpi 3.12.20-4-ARCH #1 PREEMPT Tue May 27 19:18:36 MDT 2014 armv6l GNU/Linux
# pacman -Sy
# pacman -S sudo git curl wget libunistring
# pacman -S --needed base-devel
# pacman -S --needed python2 python2-pip rng-tools libjpeg zlib sqlite3 openssl
# git clone -v --depth 1 --branch master https://github.com/OpenBazaar/OpenBazaar && cd OpenBazaar
# pip2 install -r requirements.txt
# IP=$(/sbin/ifconfig eth0 | grep 'inet ' | awk '{print $2}')
# ./run.sh -j --disable-open-browser -k $IP -q 8888 -p 12345; tail -f logs/production.log
....
....
2014-09-16 21:20:57,556 - [1] CryptoTransportLayer - INFO - Listening at: 121.254.90.62:12345
Traceback (most recent call last):
  File "node/openbazaar_daemon.py", line 269, in <module>
    args.disable_open_browser)
  File "node/openbazaar_daemon.py", line 177, in start_node
    database)
  File "node/openbazaar_daemon.py", line 46, in __init__
    dev_mode)
  File "/root/OpenBazaar/node/transport.py", line 309, in __init__
    self.listen(self.pubkey)
  File "/root/OpenBazaar/node/transport.py", line 117, in listen
    self.socket.bind('tcp://[*]:%s' % self.port)
  File "socket.pyx", line 444, in zmq.backend.cython.socket.Socket.bind (zmq/backend/cython/socket.c:4076)
  File "checkrc.pxd", line 21, in zmq.backend.cython.checkrc._check_rc (zmq/backend/cython/socket.c:6032)
zmq.error.ZMQError: Address family not supported by protocol
```

After PR

```
# pacman -Sy
# pacman -S sudo git
# git clone -v --depth 1 --branch master https://github.com/OpenBazaar/OpenBazaar && cd OpenBazaar
# ./configure.sh
# IP=$(/sbin/ifconfig eth0 | grep 'inet ' | awk '{print $2}')
# ./run.sh -j --disable-open-browser -k $IP -q 8888 -p 12345; tail -f logs/production.log
```

Related to [Trying beta with Raspberry PI but fail.：OpenBazaar](http://www.reddit.com/r/OpenBazaar/comments/2fjhn8/trying_beta_with_raspberry_pi_but_fail/)