samples: use findFile() in "python"

samples/python/floodfill.py

@@ -25,10 +25,10 @@ if __name__ == '__main__':
     try:
         fn = sys.argv[1]
     except:
-        fn = '../data/fruits.jpg'
+        fn = 'fruits.jpg'
     print(__doc__)
 
-    img = cv.imread(fn, True)
+    img = cv.imread(cv.samples.findFile(fn))
     if img is None:
         print('Failed to load image file:', fn)
         sys.exit(1)