[colcon][tf2_py] fix catkin_symlink_install error in tf2_py

[mqcmd196]

Fix the error

CMake Error at catkin_symlink_install/catkin_symlink_install.cmake:157 (message):
  catkin_symlink_install_files() can't find
  '/home/obinata/ros1/src/geometry2/tf2_py/$<TARGET_FILE:tf2_py>'
Call Stack (most recent call first):
  catkin_symlink_install/catkin_symlink_install.cmake:325 (catkin_symlink_install_files)
  cmake_install.cmake:46 (include)


---
Failed   <<< tf2_py [3.24s, exited with code 1]

when built with colcon. Please see ros#486 for details

[paulbovbel]

+1 to this fix

[mqcmd196]

@v4hn Could you check it?

[v4hn]

This lay dormant in my inbox for quite a while... Oh god, who ever considered that generator expression a "fix" 🤯

[v4hn]

Merged via cherry-pick.

I also created a proper pull-request upstream