Use panda_arm.urdf with hand arg (#83)

.setup_assistant

 moveit_setup_assistant_config:
   URDF:
     package: franka_description
-    relative_path: robots/panda_arm_hand.urdf.xacro
+    relative_path: robots/panda_arm.urdf.xacro
   SRDF:
     relative_path: config/panda_arm.srdf.xacro
   CONFIG:

launch/planning_context.launch

@@ -8,8 +8,7 @@
   <arg name="robot_description" default="robot_description"/>
 
   <!-- Load universal robot description format (URDF) -->
-  <param if="$(eval arg('load_robot_description') and arg('load_gripper'))" name="$(arg robot_description)" command="$(find xacro)/xacro '$(find franka_description)/robots/panda_arm_hand.urdf.xacro'"/>
-  <param if="$(eval arg('load_robot_description') and not arg('load_gripper'))" name="$(arg robot_description)" command="$(find xacro)/xacro '$(find franka_description)/robots/panda_arm.urdf.xacro'"/>
+  <param name="$(arg robot_description)" command="$(find xacro)/xacro $(find franka_description)/robots/panda_arm.urdf.xacro hand:=$(arg load_gripper)" />
 
   <!-- The semantic description that corresponds to the URDF -->
   <param name="$(arg robot_description)_semantic" command="$(find xacro)/xacro '$(find panda_moveit_config)/config/panda_arm_hand.srdf.xacro'" if="$(arg load_gripper)" />