Fixing javadoc warnings, provided missing package javadocs and corrected group structure.

Change-Id: I2637afe49b81e8e6d10ef3bb0f2a1cf50b2564cc
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/config/NetworkConfigService.java b/incubator/api/src/main/java/org/onosproject/incubator/net/config/NetworkConfigService.java
index 5a89ccb..85cc6ee 100644
--- a/incubator/api/src/main/java/org/onosproject/incubator/net/config/NetworkConfigService.java
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/config/NetworkConfigService.java
@@ -28,7 +28,7 @@
  */
 @Beta
 public interface NetworkConfigService
-    extends ListenerService<NetworkConfigEvent, NetworkConfigListener> {
+        extends ListenerService<NetworkConfigEvent, NetworkConfigListener> {
 
     /**
      * Returns the set of subject classes for which configuration may be
@@ -57,7 +57,8 @@
     /**
      * Returns the configuration class with the specified key.
      *
-     * @param configKey subject class name
+     * @param subjectKey subject class key
+     * @param configKey  subject class name
      * @return subject class
      */
     Class<? extends Config> getConfigClass(String subjectKey, String configKey);