use ROS_BPN in source directory in message-filters

The recipe contains a hyphen in their name, hence we must use the ROS_BPN
variable.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@oss.bmw-carit.de>

recipes-ros/ros-comm/message-filters_1.9.41.bb

@@ -7,4 +7,4 @@ DEPENDS = "boost rosconsole roscpp rostest-native rosunit-native xmlrpcpp"
 
 require ros-comm.inc
 
-S = "${WORKDIR}/ros_comm-${PV}/utilities/${BPN}"
+S = "${WORKDIR}/ros_comm-${PV}/utilities/${ROS_BPN}"