[fix] os_detect syntax error with Python 3.5 or earlier.

[130s]

Problem aimed to be resolved

143

Approach

Switch back to older format style. f-string, which seems to have become available after Py 3.6, is nice but it's only one line that is causing #143 and I'd say the current implementation is not heavily relying on f-string's advantage.

[tfoote]

I was hoping to move forward to the newer syntax over time and drop 3.5 support as I believe that all of the common distros that are supported use 3.6 or higher. What distro are you using this on with python 3.5?

Edit: Oh I see 16.04 in #143 If there was a specific short horizon where we'd be looking to support that would make sense. But with 16.04 reaching the end of an LTS release. Continuing to try to keep backwards compatibility starts to become a significant burden.

[130s]

Edit: Oh I see 16.04 in #143 If there was a specific short horizon where we'd be looking to support that would make sense. But with 16.04 reaching the end of an LTS release. Continuing to try to keep backwards compatibility starts to become a significant burden.

Yeah...we're internally maintaining our branch for 16.04 projects, which is cumbersome, but I won't expect this to be easily merged in. That said I'll keep this open for now.

[malban]

@tfoote The 0.2.4 package that is now provided by the ROS apt repo is broken on xenial by this: http://packages.ros.org/ros/ubuntu/dists/xenial/main/binary-amd64/

[tfoote]

Yes, 0.2.4 is broken due to this. However the old 0.2.3 won't work either due to #155. It's reached end of life and I am not going to fork development to support an EOL platform. To that end we've reached the point that this is no longer easy to cherry pick so I'm going to close this out as won't fix.