Compare logDir by using File object to avoid test failure on Windows which uses '\' as file separator.

Change-Id: Icef450df62467a9d43149d73833dc1fd3c75fb45
diff --git a/utils/stc/src/test/java/org/onlab/stc/CompilerTest.java b/utils/stc/src/test/java/org/onlab/stc/CompilerTest.java
index 35b200b..bf183f3 100644
--- a/utils/stc/src/test/java/org/onlab/stc/CompilerTest.java
+++ b/utils/stc/src/test/java/org/onlab/stc/CompilerTest.java
@@ -72,7 +72,7 @@
         assertEquals("incorrect step count", 24, flow.getVertexes().size());
         assertEquals("incorrect dependency count", 17, flow.getEdges().size());
         assertEquals("incorrect logDir",
-                     TEST_DIR.getAbsolutePath() + "/foo", compiler.logDir().getPath());
+                     new File(TEST_DIR.getAbsolutePath(), "foo"), compiler.logDir());
 
         Step step = compiler.getStep("there");
         assertEquals("incorrect edge count", 2, flow.getEdgesFrom(step).size());