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/web/api/src/test/java/org/onosproject/rest/resources/HostResourceTest.java b/web/api/src/test/java/org/onosproject/rest/resources/HostResourceTest.java
index 99fa074..4bb9523 100644
--- a/web/api/src/test/java/org/onosproject/rest/resources/HostResourceTest.java
+++ b/web/api/src/test/java/org/onosproject/rest/resources/HostResourceTest.java
@@ -31,7 +31,6 @@
 import org.onlab.osgi.TestServiceDirectory;
 import org.onlab.packet.IpAddress;
 import org.onlab.packet.MacAddress;
-import org.onlab.rest.BaseResource;
 import org.onosproject.codec.CodecService;
 import org.onosproject.codec.impl.CodecManager;
 import org.onosproject.net.DefaultHost;
@@ -99,7 +98,7 @@
                         .add(HostAdminService.class, mockHostService)
                         .add(CodecService.class, codecService)
                         .add(HostProviderRegistry.class, mockHostProviderRegistry);
-        BaseResource.setServiceDirectory(testDirectory);
+        setServiceDirectory(testDirectory);
     }
 
     /**