Changes type of node "robot_state_publisher" from "state_publisher" to "robot_state_publisher"

[abhishek47kashyap]

hsrb_display.launch throws the error:

ERROR: cannot launch node of type [robot_state_publisher/state_publisher]: Cannot locate node of type [state_publisher] in package [robot_state_publisher]. Make sure file exists in package path and permission is set to executable (chmod +x)

The cause, as described at Cannot locate node of type [state_publisher], is this line in that launch file:

<node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher" />

This PR updates the deprecated type="state_publisher" to type="robot_state_publisher".