jsk_topic_tools/cmake/nodelet.cmake: add random prefix before _single…

[k-okada]

…_nodelet_exec_name

I have asked personal question from a @sanketrahul about 'target with same name already exists. This will occur only when you use catkin_make, catkin build users do not encounter this error, because it is isolated build so that current cmake target will not collide with another packages's target.

�[0m�[31m�[1mCMake Error�[0m at /opt/ros/kinetic/share/jsk_topic_tools/cmake/nodelet.cmake:26 (add_executable):
�[0m  add_executable cannot create target "pointcloud_to_pcd" because another
�[0m  target with the same name already exists.  The existing target is an
�[0m  executable created in source directory
�[0m  "/home/baxter2/pcl_ros_ws/src/perception_pcl/pcl_ros".  See documentation
�[0m  for policy CMP0002 for more details.
�[0m�[36m�[4mCall Stack (most recent call first):�[0m
�[0m  jsk_recognition/jsk_pcl_ros_utils/CMakeLists.txt:102 (jsk_nodelet)

https://gist.github.com/sanketrahul/1223fa186110499f4ef01533f928b6d9

[iory]

@k-okada
I checked build failed when we use cakin_build command in jsk_common.
Also, I checked ```build succeeded`` by applyging this patch in kinetic.

[iory]

@k-okada
I did not understand the meaning of this commit.
d70ebff
Please teach me.

[k-okada]

@iory d70ebff is merged commit including a9f4f52 0397a78 0f99a57 ...

[iory]

I see. Thank you!

[furushchev]

@k-okada Is there any rationale that you randomized the prefix?
I wonder any target may miss caches in the case of catkin build --force-cmake.
How about changing __NODENAME_PREFIX to, for example, just PROJECT_NAME?

[k-okada]

@furushchev thank you for feedback, yes PROJECT_NAME would be better #1591