fix the disgnated files location in pr2_mannequin_mode

When I tried to launch like below,  
```
roslaunch pr2_teleop_general pr2_teleop_general_joystick.launch
```
I got the below error, so  I fixed each line.
```
error loading <rosparam> tag: 
file does not exist [/home/applications/ros/hydro/src/pr2_apps/pr2_mannequin_mode/pr2_arm_controllers_loose.yaml]
XML is <rosparam command="load" file="$(find pr2_mannequin_mode)/pr2_arm_controllers_loose.yaml"/>
```

- head_position_controller_loose.yaml -> config/head_position_controller_loose.yaml
- pr2_arm_controllers_loose.yaml -> config/pr2_arm_controllers_loose.yaml
- trajectory_lock.launch -> launch/trajectory_lock.launch