control: Update zone target on startup

To handle restarting of the fan control service, set the zone's target
to what's initialized on one of the fan's target that's included in the
zone.

Change-Id: I88c598e817c1dbbd42d82265b8378dc78d3946d2
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
diff --git a/control/json/zone.hpp b/control/json/zone.hpp
index e46522a..d9d6815 100644
--- a/control/json/zone.hpp
+++ b/control/json/zone.hpp
@@ -147,6 +147,16 @@
     }
 
     /**
+     * @brief Get the current target of the zone
+     *
+     * @return - The current target of the zone
+     */
+    inline const auto& getTarget() const
+    {
+        return _target;
+    }
+
+    /**
      * @brief Get the target increase delta
      *
      * @return - The current target increase delta