[Android] Remove lint warning

[Geoffrey Métais]

vlc-android | branch: 3.0.x | Geoffrey Métais <geoffrey.metais at gmail.com> | Thu Aug  2 17:26:24 2018 +0200| [6aca414cc6a8d00e2e1424f7faa718dd96405181] | committer: Geoffrey Métais

Remove lint warning

> https://code.videolan.org/videolan/vlc-android/commit/6aca414cc6a8d00e2e1424f7faa718dd96405181
---

 vlc-android/src/org/videolan/vlc/gui/helpers/UiTools.java | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/vlc-android/src/org/videolan/vlc/gui/helpers/UiTools.java b/vlc-android/src/org/videolan/vlc/gui/helpers/UiTools.java
index e8111b4c1..f1f7223cc 100644
--- a/vlc-android/src/org/videolan/vlc/gui/helpers/UiTools.java
+++ b/vlc-android/src/org/videolan/vlc/gui/helpers/UiTools.java
@@ -61,8 +61,6 @@ import android.view.DragEvent;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
-import android.view.Window;
-import android.view.WindowManager;
 import android.view.animation.Animation;
 import android.view.animation.AnimationSet;
 import android.view.animation.DecelerateInterpolator;
@@ -506,6 +504,7 @@ public class UiTools {
         }
     }
 
+    @TargetApi(Build.VERSION_CODES.N)
     public static void setOnDragListener(final Activity activity) {
         final View view = AndroidUtil.isNougatOrLater ? activity.getWindow().peekDecorView() : null;
         if (view != null) view.setOnDragListener(new View.OnDragListener() {