Fix tagging model cache

[PabstMirror]

• postInit wasn't saving p3d name to cache (wrong index)
• other functions had inverted logic for exitWith (so it still worked)
• config class isn't used, so just save bool

Could possibly cause array bounds error if a building had an odd model path (see #5035)

 7:25:43 Error in expression <aticModels setVariable [toLower (_array select ((count _array) - 2)), _cfgClass]>
 7:25:43   Error position: <select ((count _array) - 2)), _cfgClass]>
 7:25:43   Error Zero divisor

If array only had 1 element you could get something like ["x"] select -1

[commy2]

param can handle negative indices and reports default value or nil instead without error.

[PabstMirror]

The problem was that the index was just wrong,
if model = "\A3\Structures_F\Ind\PowerLines\HighVoltageColumn_F.p3d";
it was picking PowerLines instead of the p3d filename.