[0.9.8]campaigns\beta\level-04 message typo

[dtaylor84]

In data\base\campaign\level-04\control.lua:

- msg-setup-oil-industry-3 is displayed twice (lines 260 and 275); and
- msg-setup-oil-industry-4 isn't displayed at all.

This left me a bit confused about how to make plastic (thanks Google!)...

[slpwnd]

Thanks for the report, this will be fixed in 0.10.0.