Survival (Follow or identify tracks/Underground) sub-skill should not appear and has wrong value

The Survival (Follow or identify tracks/Underground) sub-sub-skill appears on any character with a rank (or even just a bonus?) in Survival and shows a wrong value (basically ignores the value of Survival – which is why it appears, seemingly).

It appears to be a known problem with these "underground" sub-sub-skills. See https://pcgenorg.atlassian.net/browse/DATA-843 for an example.

I have a fix ready to commit.