Comment 2 for bug 36625

FYI, purging nvidia-glx doesn't work when switching between nvidia-glx and nvidia-glx-legacy because both packages divert the same files. The postrm script should be modified in both packages to recognize when the other diversion is present and the remove should be bypassed.

Some good rules of thumb to apply when removing diverts in postrm scripts:
1. When multiple packages divert the same file, the postrms should skip the remove if the other divert is present. This can also happen if a package changes name.
2. In general removes should be tested before being applied in order to prevent deadlock situations.
3. Like in the report above, sometimes a file must be deleted manually before a divert remove will work.

To have a more polished distro, the postrms should anticipate and accommodate such situations.

Just my 2 cents.