Inconsistent exit codes of tools in error cases

[luator]

I just noticed that the console tools (rosnode, rostopic, ...) are inconsistent in their return code in case of errors.

The case I tested was running them without a running roscore (using kinetic):

• rostopic list --> exit code 1
• rosservice list --> exit code 2
• rosnode list --> exit code 0
• rosparam list --> exit code 1

Especially the exit code of rosnode is problematic if you expect to get an error code like with the other tools.

[dirk-thomas]

All tools should indeed return a non-zero exit code in case of errors. Some have specific codes to indicate the exact error though.

Please consider providing a pull request to fix the error code of rosnode list.

[luator]

Alright, I will try to find some time for it in the next days.