added description about what happens with set/getCacheSlots when the cache is disabled.

git-svn-id: svn://bind10.isc.org/svn/bind10/branches/trac308@2960 e5f2f494-b856-4b98-b285-d166d9295462

src/bin/auth/auth_srv.h

@@ -76,6 +76,8 @@ public:
     /// \brief Set or update the size (number of slots) of hot spot cache.
     ///
     /// If the specified size is 0, it means the size will be unlimited.
+    /// The specified size is recorded even if the cache is disabled; the
+    /// new size will be effective when the cache is enabled.
     ///
     /// This method never throws an exception.
     ///
@@ -84,6 +86,8 @@ public:
 
     /// \brief Get the current size (number of slots) of hot spot cache.
     ///
+    /// It always returns the recorded size regardless of the cache is enabled.
+    ///
     /// This method never throws an exception.
     ///
     /// \return The current number of cache slots.