fix permission problem when downloading image

app/src/main/AndroidManifest.xml

@@ -5,7 +5,7 @@
 
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
-    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="18" />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.VIBRATE" /> <!--For notifications-->
     <uses-permission android:name="android.permission.WAKE_LOCK" />  <!--Required by Eclipse Paho-->
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <!--Required by Eclipse Paho-->

app/src/main/java/com/keylesspalace/tusky/ViewMediaActivity.java

@@ -201,7 +201,7 @@ public class ViewMediaActivity extends BaseActivity implements ViewMediaFragment
     }
 
     private void downloadImage() {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN &&
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
                 ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                         != PackageManager.PERMISSION_GRANTED) {
             ActivityCompat.requestPermissions(this,