Add python_shell flag to cmdmod functions.

The cmdmod functions use shell=True by default. To allow for safer calls
add python_shell=False to the call and pass in the arguments as a
sequence

sudo salt 'dasalt' cmd.run 'ls -lh /'

sudo salt 'dasalt' cmd.run '["ls", "-lh", "/"]' python_shell=False
Merge pull request #7865 from UtahDave/shell_false

Add python_shell flag to cmdmod functions.