Remove CAR_CURRENT_SDK_VERSION from p/s/Car
This was locking our SDK version to 23, and causing doclava to not recognize several new Java 8 APIs

Test: build, flash and boot Mojave
Change-Id: I928e5abacb58030df4af7a15f7547c49934af37f
diff --git a/car-lib/api/system-current.txt b/car-lib/api/system-current.txt
index ee35126..8b75e9f 100644
--- a/car-lib/api/system-current.txt
+++ b/car-lib/api/system-current.txt
@@ -1055,12 +1055,12 @@
   }
 
   public class WearEstimateChange implements android.os.Parcelable {
-    ctor public WearEstimateChange(android.car.storagemonitoring.WearEstimate, android.car.storagemonitoring.WearEstimate, long, Instant, boolean);
+    ctor public WearEstimateChange(android.car.storagemonitoring.WearEstimate, android.car.storagemonitoring.WearEstimate, long, java.time.Instant, boolean);
     ctor public WearEstimateChange(android.os.Parcel);
     method public int describeContents();
     method public void writeToParcel(android.os.Parcel, int);
     field public static final android.os.Parcelable.Creator<android.car.storagemonitoring.WearEstimateChange> CREATOR;
-    field public final Instant dateAtChange;
+    field public final java.time.Instant dateAtChange;
     field public final boolean isAcceptableDegradation;
     field public final android.car.storagemonitoring.WearEstimate newEstimate;
     field public final android.car.storagemonitoring.WearEstimate oldEstimate;