Merge pull request square#392 from square/dimitris/null-fix

If custom transformation fails, do not invoke stats.

Author: JakeWharton

picasso/src/main/java/com/squareup/picasso/BitmapHunter.java

@@ -139,7 +139,9 @@ Bitmap hunt() throws IOException {
             bitmap = applyCustomTransformations(data.transformations, bitmap);
           }
         }
-        stats.dispatchBitmapTransformed(bitmap);
+        if (bitmap != null) {
+          stats.dispatchBitmapTransformed(bitmap);
+        }
       }
     }