Updated make_filepath test to reflect changes in picture_utils. TBR

Review URL: https://codereview.appspot.com/6350105

git-svn-id: http://skia.googlecode.com/svn/trunk@4606 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/PictureUtilsTest.cpp b/tests/PictureUtilsTest.cpp
index e744931..bb01bc9 100644
--- a/tests/PictureUtilsTest.cpp
+++ b/tests/PictureUtilsTest.cpp
@@ -11,7 +11,7 @@
 static void test_filepath_creation(skiatest::Reporter* reporter) {
     SkString result;
     SkString filename("test");
-    const char* dir = "test/path";
+    SkString dir("test/path");
     sk_tools::make_filepath(&result, dir, filename);
     REPORTER_ASSERT(reporter, result.equals("test/path/test"));
 }