Bug 845452 - Lower volume of media mochitest tests. r=roc, r=ted

build/automation.py.in

@@ -468,6 +468,7 @@ user_pref("test.mousescroll", true);
 user_pref("security.default_personal_cert", "Select Automatically"); // Need to client auth test be w/o any dialogs
 user_pref("network.http.prompt-temp-redirect", false);
 user_pref("media.cache_size", 100);
+user_pref("media.volume_scale", "0.01");
 user_pref("security.warn_viewing_mixed", false);
 user_pref("app.update.enabled", false);
 user_pref("app.update.staging.enabled", false);