Add state_pub argument to launch file

launch/description.launch

@@ -3,6 +3,7 @@
 
   <arg name="ns"            default="ana"/>
   <arg name="model"         default="ana"/>
+  <arg name="state_pub"     default="true" />
   <arg name="static_wheels" default="false" />
 
   <group ns="$(arg ns)">
@@ -10,7 +11,10 @@
     <param name="robot_description"
          command="$(find xacro)/xacro --inorder '$(find iri_ana_description)/urdf/$(arg model).xacro' name:=$(arg ns)" />
 
-    <node pkg="robot_state_publisher" type="state_publisher" name="state_publisher">
+    <node if="$(arg state_pub)"
+          pkg="robot_state_publisher"
+          type="state_publisher"
+          name="state_publisher">
       <param name="tf_prefix" type="string" value="/$(arg ns)"/>
       <param name="publish_frequency" type="double" value="20.0"/>
     </node>