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/core/SkOrderedReadBuffer.cpp b/src/core/SkOrderedReadBuffer.cpp
index 29c036e..daca74c 100644
--- a/src/core/SkOrderedReadBuffer.cpp
+++ b/src/core/SkOrderedReadBuffer.cpp
@@ -95,7 +95,7 @@
 }
 
 void* SkOrderedReadBuffer::readEncodedString(size_t* length, SkPaint::TextEncoding encoding) {
-    int32_t encodingType = fReader.readInt();
+    SkDEBUGCODE(int32_t encodingType = ) fReader.readInt();
     SkASSERT(encodingType == encoding);
     *length =  fReader.readInt();
     void* data = sk_malloc_throw(*length);