control: Separate zone creation from enabling

Separate a zone object being created from its JSON configuration and
when the zone is enabled and active. This will allow support of the use
of SIGHUP to reload the zone configuration since the zones JSON
configuration must successfully be loaded before the newly created zones
can be enabled in place of the currently enabled zones.

Change-Id: Iea6fd632898d94f3702d2b00e2ddb7f771af9168
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
diff --git a/control/json/zone.cpp b/control/json/zone.cpp
index bf11cba..d7d1a90 100644
--- a/control/json/zone.cpp
+++ b/control/json/zone.cpp
@@ -74,7 +74,10 @@
     {
         setInterfaces(jsonObj);
     }
+}
 
+void Zone::enable()
+{
     // Restore thermal control current mode state
     restoreCurrentMode();