enable the quiet argument in cmd state and module

In a continue to the thread https://groups.google.com/forum/#!topic/salt-users/lWxeOJOUVnA

I've added the quiet argument to the module and state.

Couple of notes:
* note the change I've made in line 305-307 in the cmd module, without it strerr will be output to the log file.
* while executing the cmd.run state from some reason there are still log entries, what am I missing ?

```
(UTC)[root@app ~ :) ]$ salt-call state.single cmd.run name='ls' quiet=True         
[INFO    ] Loaded configuration file: /etc/salt/minion
[INFO    ] Executing command 'ps -efH' in directory '/root'
[INFO    ] Loading fresh modules for state activity
[INFO    ] Executing state cmd.run for ls
[INFO    ] {'pid': 24319, 'retcode': 0, 'stderr': '', 'stdout': 'cdrom\ncmd.py\ncmdmod.py'}
local:
----------
    State: - cmd
    Name:      ls
    Function:  run
        Result:    True
        Comment:   Command "ls" run
        Changes:   pid: 24319
                   retcode: 0
                   stderr: 
                   stdout: cdrom
cmd.py
cmdmod.py
                   
(UTC)[root@app ~ :) ]$ salt-call state.single cmd.run name='ls'            
[INFO    ] Loaded configuration file: /etc/salt/minion
[INFO    ] Executing command 'ps -efH' in directory '/root'
[INFO    ] Loading fresh modules for state activity
[INFO    ] Executing state cmd.run for ls
[INFO    ] Executing command 'ls' in directory '/root'
[INFO    ] {'pid': 24350, 'retcode': 0, 'stderr': '', 'stdout': 'cdrom\ncmd.py\ncmdmod.py'}
local:
----------
    State: - cmd
    Name:      ls
    Function:  run
        Result:    True
        Comment:   Command "ls" run
        Changes:   pid: 24350
                   retcode: 0
                   stderr: 
                   stdout: cdrom
cmd.py
cmdmod.py

```