Fix cmake macro for service_splitter.py (#535)
Fix cmake macro for service_splitter.py (#535)

When running from a binary-installed package, the path generated by the
add_topic_service_files macro did not have a trailing slash and
would fall to properly call service_splitter.py.
swri-robotics/marti_common,swri-robotics/marti_common,swri-robotics/marti_common,swri-robotics/marti_common