[vs]: Add pip install six

[stcheng]

sonic-utilities requires six

Signed-off-by: Shu0T1an ChenG shuche@microsoft.com

[qiluo-msft]

Is it a new dependency? Why it worked before?

[lguohan]

i suspect it does not work before.

[stcheng]

see error msg:

root@b9987e019a19:/# acl-loader show session
Traceback (most recent call last):
  File "/usr/bin/acl-loader", line 9, in <module>
    load_entry_point('sonic-utilities==1.2', 'console_scripts', 'acl-loader')()
  File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 484, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2707, in load_entry_point
    return ep.load()
  File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2325, in load
    return self.resolve()
  File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2331, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/usr/lib/python2.7/dist-packages/acl_loader/main.py", line 9, in <module>
    import openconfig_acl
  File "/usr/local/lib/python2.7/dist-packages/openconfig_acl.py", line 16, in <module>
    from pyangbind.lib.yangtypes import RestrictedPrecisionDecimalType, RestrictedClassType, TypedListType
  File "/usr/local/lib/python2.7/dist-packages/pyangbind/lib/yangtypes.py", line 30, in <module>
    import six
ImportError: No module named six