sleeptest_control_unittest: example unittest for a control file

This uses the autotest shared function
file_module_loader.load_module_from_file

Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>
Merge pull request #31 from rbbratta/sleeptest_control_unittest

RFC: sleeptest_control_unittest: example unittest for a control file