Update buildings.txt and infantry_resists.txt in order to maintain current damage values after recent code changes

Update buildings.txt and infantry_resists.txt in order to maintain current damage values after recent code changes to remove variable damage values based on detonation trigger. (150 standard damage and 300 damage if triggered by vehicles)

The reason for these changes is so that all entities in explosion radius receive the expected damage value. Mines triggered by vehicles would cause all entities inside the radius to have double damage; this change removes that weird behaviour.