fix warning from scalar --> int32 conversion

BUG=

Review URL: https://codereview.appspot.com/7065050

git-svn-id: http://skia.googlecode.com/svn/trunk@7061 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/animator/SkScriptTokenizer.cpp b/src/animator/SkScriptTokenizer.cpp
index a1de5e5..ca6cab0 100644
--- a/src/animator/SkScriptTokenizer.cpp
+++ b/src/animator/SkScriptTokenizer.cpp
@@ -993,7 +993,7 @@
                 SkASSERT(arrayValue.fType == SkOperand2::kArray);  // !!! add error handling
                 SkOpArray* array = arrayValue.fOperand.fArray;
                 SkOperand2 operand;
-                bool success = array->getIndex(index, &operand);
+                SkDEBUGCODE(bool success = ) array->getIndex(index, &operand);
                 SkASSERT(success); // !!! add error handling
                 SkScriptValue2 resultValue;
                 resultValue.fType = array->getType();