iOS: Clearing out old keychain if app is re-installed

gistfile1.txt

//Clear keychain on first run in case of reinstallation
    if (![[NSUserDefaults standardUserDefaults] objectForKey:@"FirstRun"]) {
        // Delete values from keychain here
        if ([[BXTAccountManager sharedAccountManager] authenticatedAccounts]) {
            [[BXTNotificationsManager sharedNotificationsManager] removeAllAccountsFromServer];
        }
        
        [[BXTAccountManager sharedAccountManager] clearKeychain];
        NSLog(@"Clearing keychain");
        [[NSUserDefaults standardUserDefaults] setValue:@"1strun" forKey:@"FirstRun"];
        [[NSUserDefaults standardUserDefaults] synchronize];
		}