OSError: [Errno 22] Invalid argument - caused by duplicate gids.

Currently, `supgroups` can return a list that has duplicate gids in it:
```python
>>> supgroups = [g.gr_gid for g in grp.getgrall() if uinfo.pw_name in g.gr_mem and g.gr_gid != uinfo.pw_gid]
>>> supgroups
[80, 29, 1, 2, 5, 9, 8, 20, 3, 4, 1, 2, 3, 4, 5, 8, 9, 20, 29, 80]
```

This cause problems in the comparison on [L80](https://github.com/saltstack/salt/blob/0.17/salt/modules/cmdmod.py#L80).  More importantly, it causes an OS error on [L82](https://github.com/saltstack/salt/blob/0.17/salt/modules/cmdmod.py#L82) when we attempt to `os.setgroups(supgroups)`.  Simply deduplicating the list before handling processing it fixes the issue.

Here's some debugging that should help you understand:
```python
>>> uinfo
pwd.struct_passwd(pw_name='root', pw_passwd='*', pw_uid=0, pw_gid=0, pw_gecos='System Administrator', pw_dir='/var/root', pw_shell='/bin/sh')
>>> [g.gr_gid for g in grp.getgrall()]
[83, 55, 87, 81, 79, 33, 67, 235, 97, 93, 32, 82, 202, 212, 72, 207, 59, 204, 220, 227, 56, 201, 25, 96, 84, 30, 211, 205, 26, 98, 100, 78, 54, 65, 74, 222, 228, 24, 209, 28, 27, 216, 76, 60, 203, 31, 92, 58, 200, 89, 75, 73, 13, 94, 210, 91, 208, 99, 95, 213, 66, 224, 221, 88, 70, 90, 80, 50, 7, 29, 401, 53, 1, 68, 12, 16, 51, 2, 61, 6, 62, 52, 69, 4294967294, 4294967295, 5, 10, 9, 8, 20, 3, 4, 45, 0, 2106269579, 4294967294, 4294967295, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 16, 20, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 45, 50, 51, 52, 53, 54, 55, 56, 58, 59, 60, 61, 62, 65, 66, 67, 68, 69, 70, 72, 73, 74, 75, 76, 78, 79, 80, 81, 82, 83, 84, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 200, 201, 202, 203, 204, 205, 207, 208, 209, 210, 211, 212, 213, 216, 220, 221, 222, 224, 227, 228]
>>> supgroups = [g.gr_gid for g in grp.getgrall() if uinfo.pw_name in g.gr_mem and g.gr_gid != uinfo.pw_gid]
>>> supgroups
[80, 29, 1, 2, 5, 9, 8, 20, 3, 4, 1, 2, 3, 4, 5, 8, 9, 20, 29, 80]
>>> # Notice the duplication ...
...
>>> 
>>> os.getgroups()
[0, 1, 2, 3, 4, 5, 8, 9, 12, 20, 29, 61, 80]
>>> os.setgroups(supgroups)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: [Errno 22] Invalid argument
>>> type(supgroups)
<type 'list'>
>>> seen = set()
>>> supgroups_deduped = [ x for x in supgroups if x not in seen and not seen.add(x) ]
>>> supgroups_deduped
[80, 29, 1, 2, 5, 9, 8, 20, 3, 4]
>>> os.setgroups(supgroups_deduped)
>>> os.getgroups()
[0, 1, 2, 3, 4, 5, 8, 9, 12, 20, 29, 61, 80]
```

Solution gleened from:
http://stackoverflow.com/a/480227/615422

```sh
# /usr/local/bin/salt-minion --versions-report
           Salt: 0.16.3
         Python: 2.7.2 (default, Oct 11 2012, 20:14:37)
         Jinja2: 2.7.1
       M2Crypto: 0.21.1
 msgpack-python: 0.3.0
   msgpack-pure: Not Installed
       pycrypto: 2.6
         PyYAML: 3.10
          PyZMQ: 13.1.0
            ZMQ: 3.2.3
```
OS X 10.8.4
Properly support decompressing `tar` files. Refs #7244.
Properly format the call(missing white-space).
Merge pull request #7634 from s0undt3ch/0.17

archive.tar fix
Check PEP8 using Pylint
Check PEP8 using Pylint
Modify socket delletion to handle minor api change in pyzmq 14
Add another sticky bit
Fix parsing
Add key_auto deploy more correctly
fix for issue #7436 no templates in salt

One line in setup.py that says salt.templates package should be build.
Dereferenced symbolic links when creating thin.tgz
Pass through the env to file.patch state

Fixes #7452.
updated suse spec to salt 0.17.0

created salt-ssh as a separate package
improved dependencies per package
salt-master depends pyzmq and recommends halite
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salt dependency pyzmq removed.
client/ssh/wrapper/config.py: rm unused import of urllib2

************* Module salt.client.ssh.wrapper.config
salt/client/ssh/wrapper/config.py:9: [W0611(unused-import), ] Unused import urllib2
Add packaging convention document
Add "available" functions to service providers

These functions make service states more reliable, and and fix edge
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doesn't have an available function (and this falls back to using the
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Fix reporting for service.dead states

service.dead states for which the "enable" param is not set to True or
False, if a service is stopped as a result of running the state, did not
have anything in the changes dict, and also had an empty comment field.
This commit improves those reporting deficiencies.

In addition, the helper function _available() in salt/states/service.py
has been modified slightly. There is no reason to add a key to the
return dict, then pop it off after running _available(). This has been
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Fix minor documentation bug in states.mount.unmount
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