Fix non-existent dependency warning for the catkin API (fix #7)

cmake/genjava-catkin-api.cmake.em

@@ -52,7 +52,6 @@ macro(generate_rosjava_messages)
   set(build_dir_to_be_cleaned_list)
   foreach(pkg ${ARG_PACKAGES})
     list(APPEND build_dir_to_be_cleaned_list "${CMAKE_CURRENT_BINARY_DIR}/${pkg}")
-    add_dependencies(${PROJECT_NAME}_generate_artifacts ${pkg}_generate_messages)
   endforeach()
   set_directory_properties(PROPERTY ADDITIONAL_MAKE_CLEAN_FILES "${build_dir_to_be_cleaned_list}")
 endmacro()