Bug 1345728 - Intermittent netwerk/test/mochitests/test_user_agent_updates.html- fix preferences for testing. r=mcmanus

MozReview-Commit-ID: LN8xrBBNRkN

testing/profiles/prefs_general.js

@@ -229,6 +229,7 @@ user_pref("browser.snippets.firstrunHomepage.enabled", false);
 
 // Disable useragent updates.
 user_pref("general.useragent.updates.enabled", false);
+user_pref("general.useragent.updates.url", "https://example.com/0/%%APP_ID%%");
 
 // Disable webapp updates.  Yes, it is supposed to be an integer.
 user_pref("browser.webapps.checkForUpdates", 0);