Add joint tag in gripper tag of SRDF

srdf/talos.srdf

@@ -649,10 +649,12 @@ TALOS disabled collisions generated by Moveit! using the moveit_setup_assistant.
     <gripper name="left_gripper" clearance="0.03">
       <position> 0 0 -0.13 0.707106 0 0.707106 0</position>
       <link name="gripper_left_base_link" />
+      <joint name="gripper_left_joint" />
     </gripper>
 
     <gripper name="right_gripper" clearance="0.03">
       <position> 0 0 -0.13 0 -0.707106 0 0.707106 </position>
       <link name="gripper_right_base_link" />
+      <joint name="gripper_right_joint" />
     </gripper> 
 </robot>