modules/Utils.jsm: fix assignment to undeclared variable
chrome/content/Dialog.js: remove deprecated octal literal
chrome/content/ExtInit.js: comment was started with single slash
chrome/content/Dialog.js: add 7th parameter to the call of saveURI

nsIWebBrowserPersist API was broken in FF18.  See https://bugzilla.mozilla.org/show_bug.cgi?id=820522