Bug 992398 fix domain for cdn deployment of directory site, r=gavin

modules/libpref/src/init/all.js

@@ -4239,7 +4239,7 @@ pref("memory.blob_report.stack_frames", 0);
 pref("social.whitelist", "https://mozsocial.cliqz.com,https://now.msn.com,https://mixi.jp");
 // comma separated list of domain origins (e.g. https://domain.com) for
 // directory websites (e.g. AMO) that can install providers for other sites
-pref("social.directories", "https://activations.mozilla.org");
+pref("social.directories", "https://activations.cdn.mozilla.net");
 // remote-install allows any website to activate a provider, with extended UI
 // notifying user of installation. we can later pref off remote install if
 // necessary. This does not affect whitelisted and directory installs.