[pr2eus] go-pos-unsafe return `t` when the motion is correctly executed.

[knorth55]

now :go-pos-unsafe always return nil in kinematics simulation and cmd_vel case. this PR changes to return t in kinematics simulation and cmd_vel case.

• kinematics simulation case
  • the robot moves in :go-pos-unsafe-no-wait
  • :go-pos-unsafe-no-wait returns t
  • dont run :go-pos-unsafe-wait because of or
  • so, :go-pos-unsafe returns t
• cmd_vel case
  • the robot moves in :go-pos-unsafe-no-wait
  • :go-pos-unsafe-no-wait returns t
  • dont run :go-pos-unsafe-wait because of or
  • so, :go-pos-unsafe returns t
• move_base_trajecotry_action case case
  • the robot publish goal to action in :go-pos-unsafe-no-wait
  • the robot wait for the action in :go-pos-unsafe-wait
  • :go-pos-unsafe-no-wait returns nil
  • :go-pos-unsafe-wait returns t or nil (it depends on action result)
  • so, :go-pos-unsafe returns t or nil (it depends on action result)