addon_updater.py attempts to create folders and fails if installed with read only permissions

[ragtag]

Describe the bug
When you try to load the plug-in, the addon_updater.py attempts to create a folder. If you've installed MB-Lab to a read only location, you get a Permission denied error, and MB-Lab fails to load. Adding a simple test for write permissions, or wrapping it in a try/except, would fix the problem.

For home users, this is not a big problem, but when installing Blender at a studio, artists generally won't have write permissions to folders where the software is installed. Also note that at many bigger studios workstations don't have internet access for security reasons, so any attempt at an online update would fail there too.

To Reproduce
1.Install MB-Lab to a read only location
2. Start Blender
3. Load MB-Lab
4. You get Permission error

Expected behavior
For MB-Lab to load as normal, and possibly give a warning that it was unable to check for updates.

It's possible this bug report should just be passed on to, https://github.com/CGCookie/blender-addon-updater as it looks like this feature is coming from there.

[animate1978]

So I have looked into this, it seems that this is a known issue so adding a new issue ticket to their repo won't do much. I will make a reference to this issue though.

Their recommendation is to pre include folders that need to be created, in this case it is mb-lab_updater.

However this still doesn't fully solve the situation for updating after successful installation and exec.

[animate1978]

CGCookie/blender-addon-updater#30 (comment)