Bug 993326 - Don't directly set the dom.mozApps.auto_confirm_install preference in test_operator_app_install. r=fabrice

dom/apps/tests/test_operator_app_install.js

@@ -141,7 +141,6 @@ function go() {
 }
 
 function finish() {
-  SpecialPowers.setBoolPref('dom.mozApps.auto_confirm_install', false);
   SimpleTest.finish();
 }