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/gpu/GrPathUtils.cpp b/src/gpu/GrPathUtils.cpp
index 4092959..d3d784c 100644
--- a/src/gpu/GrPathUtils.cpp
+++ b/src/gpu/GrPathUtils.cpp
@@ -251,7 +251,7 @@
         m.postConcat(UVpts);
 
         // The matrix should not have perspective.
-        static const SkScalar gTOL = SkFloatToScalar(1.f / 100.f);
+        SkDEBUGCODE(static const SkScalar gTOL = SkFloatToScalar(1.f / 100.f));
         GrAssert(SkScalarAbs(m.get(SkMatrix::kMPersp0)) < gTOL);
         GrAssert(SkScalarAbs(m.get(SkMatrix::kMPersp1)) < gTOL);