For a username/password prompt, allow saving of the password even if the username is blank.

toolkit/components/passwordmgr/base/nsSingleSignonPrompt.cpp

@@ -158,7 +158,7 @@ nsSingleSignonPrompt::PromptUsernameAndPassword(const PRUnichar* aDialogTitle,
                                      aConfirm);
 
   if (*aConfirm) {
-    if (checkValue && user[0] != '\0') {
+    if (checkValue && (user[0] != '\0' || password[0] != '\0')) {
       // The user requested that we save the values
       // TODO: support SAVE_PASSWORD_FOR_SESSION