Ignoring stale orders/unknown status of commands when stopping and restarting sheriff

[heuristicus]

• Start the sheriff with rosrun procman_ros sheriff robot.pmd
• Start a deputy with rosrun procman_ros deputy -i localhost.
• Start the new lab script, then stop the nodes and exit the sheriff.

The deputy spawned remains active. Start another sheriff with the same command and you will see Unknown as the command status, and ignoring stale orders (utime 1592826401 seconds ago). You may want to check the system clocks! in the output textbox.

Something strange happens with rospy.Time.now(). Usually the output of rospy.loginfo(rospy.Time.now()) looks like

[INFO] [1592907490.947916]: 1592907490857603073

But when this error is happening, the output looks like

[INFO] [1592907442.854022, 0.000000]: 0

It looks like this may be caused by gazebo publishing the clock, according to https://answers.ros.org/question/300956/rospytimenow-returns-0/

Need to make a decision on whether to continue to use wall clock time in the time comparisons in sheriff/deputy or stick to using ros time only. Currently there is a mismatch in some places.