Simplify stack upgrade

wo/cli/plugins/stack_pref.py

@@ -1114,7 +1114,7 @@ def post_pref(self, apt_packages, packages):
             WOService.reload_service(self, 'proftpd')
 
     # Redis configuration
-    if set(["redis-server"]).issubset(set(apt_packages)):
+    if set(WOVariables.wo_redis).issubset(set(apt_packages)):
         # set redis.conf parameter
         # set maxmemory 10% for ram below 512MB and 20% for others
         # set maxmemory-policy allkeys-lru

wo/cli/plugins/stack_upgrade.py

@@ -149,12 +149,7 @@ class WOStackUpgradeController(CementBaseController):
                       "releases/download/v{0}/wordops-dashboard.tar.gz"
                       .format(WOVariables.wo_dashboard),
                       "/var/lib/wo/tmp/wo-dashboard.tar.gz",
-                      "WordOps Dashboard"],
-                     ["https://github.com/soerennb/"
-                      "extplorer/archive/v{0}.tar.gz"
-                      .format(WOVariables.wo_extplorer),
-                      "/var/lib/wo/tmp/extplorer.tar.gz",
-                      "eXtplorer"]]
+                      "WordOps Dashboard"]]
 
         if pargs.phpmyadmin:
             if os.path.isdir('/var/www/22222/htdocs/db/pma'):
@@ -177,7 +172,6 @@ class WOStackUpgradeController(CementBaseController):
             else:
                 Log.error(self, "Composer isn't installed")
 
-        if len(packages) or len(apt_packages):
         if len(apt_packages):
             Log.info(self, "Your site may be down for few seconds if "
                      "you are upgrading Nginx, PHP-FPM, MariaDB or Redis")