message: Fix 1700 AD starting slaves
diff: @@ -27742,19 +27742,19 @@ BeginPlot
  UnitType=UNIT_CATAPULT, UnitOwner=37, (Congo)
  EndUnit
  BeginUnit
  - UnitType=UNIT_NATIVE_SLAVE, UnitOwner=37, (Congo)
  + UnitType=UNIT_SLAVE, UnitOwner=37, (Congo)
  EndUnit
  BeginUnit
  - UnitType=UNIT_NATIVE_SLAVE, UnitOwner=37, (Congo)
  + UnitType=UNIT_SLAVE, UnitOwner=37, (Congo)
  EndUnit
  BeginUnit
  - UnitType=UNIT_NATIVE_SLAVE, UnitOwner=37, (Congo)
  + UnitType=UNIT_SLAVE, UnitOwner=37, (Congo)
  EndUnit
  BeginUnit
  - UnitType=UNIT_NATIVE_SLAVE, UnitOwner=37, (Congo)
  + UnitType=UNIT_SLAVE, UnitOwner=37, (Congo)
  EndUnit
  BeginUnit
  - UnitType=UNIT_NATIVE_SLAVE, UnitOwner=37, (Congo)
  + UnitType=UNIT_SLAVE, UnitOwner=37, (Congo)
  EndUnit
  BeginUnit
  UnitType=UNIT_SETTLER, UnitOwner=37, (Congo)
  