catkin.bbclass: adding .debug files to the dbg package

In the topic-tools recipe, a QA error was raised as the .debug files were put
into the main package. By adding this line in the catkin class, the files are
now placed in the dbg package.

classes/catkin.bbclass

@@ -45,6 +45,10 @@ FILES_${PN}-dev += "\
     ${datadir}/${ROS_BPN}/*.template \
     "
 
+FILES_${PN}-dbg += "\
+    ${libdir}/${ROS_BPN}/.debug/* \
+    "
+
 SYSROOT_PREPROCESS_FUNCS += "catkin_sysroot_preprocess"
 
 catkin_sysroot_preprocess () {