Re-enable settings cache after news schema check.

Fix a copy/paste typo that's been in place for a couple year and that left
the settings cache disabled after the MythNews DB schema check.  This wasn't
usually visible because anyone who had any "later-in-the-alphabet" plugin
installed (such as MythWeather or MythVideo) would have their settings cache
re-enabled by the later plugin's schema check.  However, now that the
MythVideo schema is in core schema (and so no MythVideo schema check is done),
users without MythWeather would have seen slowness until they forced the
settings cache to re-enable (such as by going through any settings pages).

Thanks to Greg Estabrooks for noticing.
(cherry picked from commit 6f63367)

mythplugins/mythnews/mythnews/main.cpp

@@ -69,7 +69,7 @@ int mythplugin_init(const char *libversion)
                 "Couldn't upgrade database to new schema, exiting.");
         return -1;
     }
-    gCoreContext->ActivateSettingsCache(false);
+    gCoreContext->ActivateSettingsCache(true);
 
     setupKeys();