fix(saveload): Check version instead of currentVersion in xfer methods

[bobtista]

• Fixes Xfer: check against version variable not currentVersion #3297

InGameUI::xfer, CountermeasuresBehavior::xfer and GameStateMap::xfer compare currentVersion against the version a field was added in:

if( currentVersion >= 2 )
{
    xfer->xferSTLObjectIDVector( &m_counterMeasures );
    ...
}

currentVersion is a constant, so this is always true and the code for older versions never runs. InGameUI has an else that falls back to ready for the EVA flag. It is dead.

Now all three check version. Save output does not change, version and currentVersion are equal when saving.

Retail wrote version 3 for InGameUI and version 2 for the other two. Every real save already takes these branches and loads exactly as before. Nothing user facing changes, the reads now match the version comments above them.

DamageInfoInput::xfer is the sixth site from the issue. That one crashes, so it has its own issue and pull, #3299.

Todo:

• No currentVersion >= comparisons left in Core, Generals or GeneralsMD
• Zero Hour saves and loads as before
• Replicate to Generals — GameStateMap only, the other two files are Zero Hour only