Fixed 'catkin profile set ...' error message

[racko]

Calling 'catkin profile set random_garbage', users where being presented
with 'catkin profile: error: Profile r does not exist ...'

[racko]

Here's the CI output. I guess that's not my fault, right?

The path /usr/local/bin/python3 (from --python=/usr/local/bin/python3) does not exist
.travis.before_install.bash: line 12: venv/bin/activate: No such file or directory
The command "source .travis.before_install.bash" failed and exited with 1 during .
Your build has been stopped.
/Users/travis/.travis/job_stages: line 166: shell_session_update: command not found

[mikepurvis]

Looks like a good change, thanks!