fix docker run ImportError: No module named pybitcointools

docker run problem
```
$ git clone https://github.com/OpenBazaar/OpenBazaar
$ cd OpenBazaar
$ sudo  docker build -t=test/ob .
$ sudo  docker run -i -t test/ob /bin/bash
root@12cb00b6e3d7:/bazaar# bash run.sh
/usr/bin/python2
Production Mode
File ob.db does not exist. Running setup script.
DB_PATH db/ob.db
Traceback (most recent call last):
  File "node/tornadoloop.py", line 8, in <module>
    from crypto2crypto import CryptoTransportLayer
  File "/bazaar/node/crypto2crypto.py", line 21, in <module>
    from pybitcointools import *
ImportError: No module named pybitcointools
```
referred to the configure.sh and provide the bind 127.0.0.1 workround.
```
$ git clone https://github.com/OpenBazaar/OpenBazaar
$ cd OpenBazaar
$ sudo docker build -t=test/ob .
$ sudo docker run -d -p 8888:8888 test/ob
$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND                CREATED             STATUS              PORTS                                                   NAMES
79a3d6b545dc        test/ob:latest      /bin/sh -c 'bash run   23 minutes ago      Up 23 minutes       12345/tcp, 8889/tcp, 8890/tcp, 0.0.0.0:8888->8888/tcp   tender_wilson
$ curl -v http://YOUR_DOCKER_HOST_IP:8888
* Hostname was NOT found in DNS cache
*   Trying 192.168.1.79...
* Connected to 192.168.1.79 (192.168.1.79) port 8888 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.35.0
> Host: 192.168.1.79:8888
> Accept: */*
>
< HTTP/1.1 302 Found
< Date: Mon, 01 Sep 2014 07:42:20 GMT
< Content-Length: 0
< Content-Type: text/html; charset=UTF-8
< Location: /html/index.html
* Server TornadoServer/4.0.1 is not blacklisted
< Server: TornadoServer/4.0.1
```

Is there any way to setup  node/tornadoloop.py http_ip ?
Not sure why you're installing `python-pip` again?