Revert "Update min_sdk_version from SdkSpec to ApiLevel"

Revert submission 2457063

Reason for revert: Broken udc-dev

Reverted changes: /q/submissionid:2457063

Change-Id: Id6349fc1318877044af713c914a0afd437d3d2d5
diff --git a/apex/apex.go b/apex/apex.go
index 9e9d742..b2ca6c4 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -2946,8 +2946,12 @@
 }
 
 // Returns apex's min_sdk_version SdkSpec, honoring overrides
-func (a *apexBundle) MinSdkVersion(ctx android.EarlyModuleContext) android.ApiLevel {
-	return a.minSdkVersion(ctx)
+func (a *apexBundle) MinSdkVersion(ctx android.EarlyModuleContext) android.SdkSpec {
+	return android.SdkSpec{
+		Kind:     android.SdkNone,
+		ApiLevel: a.minSdkVersion(ctx),
+		Raw:      a.minSdkVersionValue(ctx),
+	}
 }
 
 // Returns apex's min_sdk_version ApiLevel, honoring overrides