Small refactor of download repo and FlashZip

app/src/main/java/com/topjohnwu/magisk/receivers/DownloadReceiver.java

@@ -12,15 +12,11 @@ import com.topjohnwu.magisk.R;
 
 public abstract class DownloadReceiver extends BroadcastReceiver {
     public Context mContext;
-    public String mName;
+    public String mFilename;
     long downloadID;
 
     public DownloadReceiver() {}
 
-    public DownloadReceiver(String name) {
-        mName = name;
-    }
-
     @Override
     public void onReceive(Context context, Intent intent) {
         mContext = context;
@@ -51,5 +47,9 @@ public abstract class DownloadReceiver extends BroadcastReceiver {
         downloadID = id;
     }
 
+    public void setFilename(String filename) {
+        mFilename = filename;
+    }
+
     public void task(Uri uri) {}
 }