Early return when the scale is 0.

b/24534579

Change-Id: Ib3581ec99387ca70ca036026f64857a49657d94b
diff --git a/libs/hwui/SpotShadow.cpp b/libs/hwui/SpotShadow.cpp
index 9b0a1aa..bdce73c 100644
--- a/libs/hwui/SpotShadow.cpp
+++ b/libs/hwui/SpotShadow.cpp
@@ -1051,7 +1051,7 @@
  */
 void SpotShadow::dumpPolygon(const Vector3* poly, int polyLength, const char* polyName) {
     for (int i = 0; i < polyLength; i++) {
-        ALOGD("polygon %s i %d x %f y %f", polyName, i, poly[i].x, poly[i].y);
+        ALOGD("polygon %s i %d x %f y %f z %f", polyName, i, poly[i].x, poly[i].y, poly[i].z);
     }
 }