fix: implement downgrade for sql transfer table (#2056)

Resolves: #1872

Author: jamesonwilliams

aws-android-sdk-s3/src/main/java/com/amazonaws/mobileconnectors/s3/transferutility/TransferDatabaseHelper.java

@@ -27,6 +27,7 @@ class TransferDatabaseHelper extends SQLiteOpenHelper {
     // the database is being upgraded.
     private static final int DATABASE_VERSION = 6;
 
+    private final Context context;
     private int version;
 
     public TransferDatabaseHelper(Context context) {
@@ -35,6 +36,7 @@ public TransferDatabaseHelper(Context context) {
 
     public TransferDatabaseHelper(Context context, int version) {
         super(context, DATABASE_NAME, null, version);
+        this.context = context;
         this.version = version;
     }
 
@@ -48,4 +50,9 @@ public void onUpgrade(SQLiteDatabase database, int oldVersion, int newVersion) {
         TransferTable.onUpgrade(database, oldVersion, newVersion);
     }
 
+    @Override
+    public void onDowngrade(SQLiteDatabase database, int oldVersion, int newVersion) {
+        context.deleteDatabase(DATABASE_NAME);
+        onCreate(database);
+    }
 }