Merge pull request #493 from markjaquith/issue/array-offset-on-null

Ensure that getZoneSetting() returns a value key before attempting to access it

src/WordPress/Hooks.php

@@ -519,7 +519,7 @@ private function pageRuleContains($pagerules, $key, $value)
     private function zoneSettingAlwaysUseHTTPSEnabled($zoneTag)
     {
         $settings = $this->api->getZoneSetting($zoneTag, "always_use_https");
-        return $settings["value"] == "on";
+        return !empty($settings["value"]) && $settings["value"] == "on";
     }