func_timer run: Convert "none" time-out to None
func_timer run: Convert "none" time-out to None

- As a convenience to the caller who may be passing along an
  external parm value, added code to convert time_out value of "none" to
  None.
- Added code to verify that time_out is non-negative.
- Removed useless test for len(kwargs).

Change-Id: I504e36fb78094fa22a2225423d859bf3111d7bb8
Signed-off-by: Michael Walsh <10404802c7de463f402c4a18638106ca1b12ef61@us.ibm.com>

openbmc/openbmc-test-automation,openbmc/openbmc-test-automation