Bug#1000302: datadir patch has priority issue

[ieiao]

Recently, when running the game, I found that this patch also has a 
search path priority problem.

When I try the Art Revolution mod (https://addons.wz2100.net/292), it 
does not work nomarly.

In the end I found that the problem was caused by the high priority of 
the search path added by the datadir patch. After I adjusted its 
priority to 5, the mod worked properly first.