Remove traling commas to make json valid

common/test/data/graphic_slider_tool/policies/2012_Fall.json

@@ -9,6 +9,6 @@
         "display_name": "Overview"
     },
     "graphical_slider_tool/sample_gst": {
-        "display_name": "Sample GST",
-    },
+        "display_name": "Sample GST"
+    }
 }

common/test/data/self_assessment/policies/2012_Fall.json

@@ -9,6 +9,6 @@
         "display_name": "Overview"
     },
     "selfassessment/SampleQuestion": {
-        "display_name": "Sample Question",
-    },
+        "display_name": "Sample Question"
+    }
 }