Added @Beta annotations to the network configuration API.

Change-Id: I6b0e4f2064509a26e546735baef087e621ad8307
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/config/Config.java b/incubator/api/src/main/java/org/onosproject/incubator/net/config/Config.java
index 7018c65..dacef68 100644
--- a/incubator/api/src/main/java/org/onosproject/incubator/net/config/Config.java
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/config/Config.java
@@ -17,6 +17,7 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.google.common.annotations.Beta;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
@@ -26,6 +27,7 @@
  *
  * @param <S> type of subject
  */
+@Beta
 public abstract class Config<S> {
 
     protected ObjectMapper mapper;