Fixing Javadoc errors

Change-Id: I72b9d49e052316cbbbef343d367ffffe13cd4e56
diff --git a/apps/dhcp/src/main/java/org/onosproject/dhcp/DhcpStore.java b/apps/dhcp/src/main/java/org/onosproject/dhcp/DhcpStore.java
index 5615af1..e263b3a 100644
--- a/apps/dhcp/src/main/java/org/onosproject/dhcp/DhcpStore.java
+++ b/apps/dhcp/src/main/java/org/onosproject/dhcp/DhcpStore.java
@@ -64,6 +64,7 @@
      * Releases the IP assigned to a Mac ID into the free pool.
      *
      * @param hostId the host ID for which the mapping needs to be changed
+     * @return released ip
      */
     Ip4Address releaseIP(HostId hostId);