remove un-needed use statement

The latest yocto flags an error, indicating the redeclaration of
"using ActivationInherit::activation;". The code does not match the
doxygen and it is declared twice. The use statement does not appear to
be needed so just remove it all.

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: I849b52fad61a96190195ffa64c4aca20c9bedbc8
diff --git a/activation.hpp b/activation.hpp
index 41ff1cd..c236c9b 100644
--- a/activation.hpp
+++ b/activation.hpp
@@ -178,12 +178,6 @@
     }
     virtual ~Activation() = default;
 
-    /** @brief Activation property get function
-     *
-     *  @returns One of Activation::Activations
-     */
-    using ActivationInherit::activation;
-
     /** @brief Overloaded requestedActivation property setter function
      *
      *  @param[in] value - One of Activation::RequestedActivations
@@ -235,12 +229,6 @@
     /** @brief Used to subscribe to dbus systemd signals **/
     sdbusplus::bus::match_t systemdSignals;
 
-    /** @brief activation status property get function
-     *
-     * @returns Activations - The activation value
-     */
-    using ActivationInherit::activation;
-
     /**
      * @brief Determine the configured image apply time value
      *