Fix binary compatibility of opencv_stitching

modules/stitching/include/opencv2/stitching/detail/warpers.hpp

@@ -70,8 +70,8 @@ public:
 
     virtual Rect warpRoi(Size src_size, const Mat &K, const Mat &R) = 0;
 
-    virtual float getScale() const { return 1.f; }
+    float getScale() const { return 1.f; }
-    virtual void setScale(float) {}
+    void setScale(float) {}
 };
 
 
@@ -134,6 +134,8 @@ class CV_EXPORTS PlaneWarper : public RotationWarperBase<PlaneProjector>
 public:
     PlaneWarper(float scale = 1.f) { projector_.scale = scale; }
 
+    void setScale(float scale) { projector_.scale = scale; }
+
     Point2f warpPoint(const Point2f &pt, const Mat &K, const Mat &R, const Mat &T);
 
     Rect buildMaps(Size src_size, const Mat &K, const Mat &R, const Mat &T, Mat &xmap, Mat &ymap);