Removed the setServiceDirectory() method from the base web resource

This is a testing only API and potentially dangerous to allow to be public.
I modified the tests that use it to set the value using TestUtils.setField()

Change-Id: Ic590f4641f4e3de208dffa16b3df9a9a2106114b
diff --git a/apps/vtn/vtnweb/src/test/java/org/onosproject/vtnweb/resources/PortPairResourceTest.java b/apps/vtn/vtnweb/src/test/java/org/onosproject/vtnweb/resources/PortPairResourceTest.java
index 7f73b83..63e89b9 100644
--- a/apps/vtn/vtnweb/src/test/java/org/onosproject/vtnweb/resources/PortPairResourceTest.java
+++ b/apps/vtn/vtnweb/src/test/java/org/onosproject/vtnweb/resources/PortPairResourceTest.java
@@ -22,7 +22,6 @@
 import org.junit.Test;
 import org.onlab.osgi.ServiceDirectory;
 import org.onlab.osgi.TestServiceDirectory;
-import org.onlab.rest.BaseResource;
 import org.onosproject.codec.CodecService;
 import org.onosproject.vtnrsc.PortPair;
 import org.onosproject.vtnrsc.PortPairId;
@@ -135,7 +134,7 @@
         SfcCodecContext context = new SfcCodecContext();
         ServiceDirectory testDirectory = new TestServiceDirectory().add(PortPairService.class, portPairService)
                 .add(CodecService.class, context.codecManager());
-        BaseResource.setServiceDirectory(testDirectory);
+        setServiceDirectory(testDirectory);
 
     }