Fix a bug that prevented completion to work when 'print_help' parameter was used.
Fix a bug that prevented completion to work when 'print_help' parameter was used.

'argcomplete' module for completion monkey patch the '_parse_known_args' method
of the 'argparse.ArgumentParser' object. 'print_help' function also monkey
patch this method ... Correct the function for detecting when 'argcomplete' is
used and returning the 'argcomplete' patched method.

fmenabe/python-clg