bug#20541: ERC password fetching using Secret Service API is broken

[Krzysztof Jurewicz <krzysztof.jurewicz@gmail.com>]

When trying to store ERC passwords using Secret Service API (i.e. when
using GNOME Keyring), ERC breaks when trying to join a channel.

Steps to reproduce:

⒈ Run emacs -Q.
⒉ Eval (require 'auth-source).
⒊ Eval (setq auth-sources '("secrets:FOO")), where FOO is an existing
keyring name.
⒋ Open ERC.
⒌ Try to connect to Freenode using the default settings.

What happens:
The following error is displayed:
auth-source-secrets-listify-pattern: Wrong type argument: sequencep, 6667

What should happen:
I should connect to Freenode.

One possible patch is attached below. This is the simplest solution; I
have not thought much about whether it may be more desirable to convert
numbers to strings inside the secrets.el package.

From 25f798b3b86a34bd6b262c59c3733d72eec50c13 Mon Sep 17 00:00:00 2001
From: Krzysztof Jurewicz <krzysztof.jurewicz@gmail.com>
Date: Thu, 7 May 2015 13:01:24 +0200
Subject: [PATCH] * lisp/erc/erc.el (erc-open): Fix password fetching

ERC used to pass the port number as a number, however when using
Secret Service API, only strings can be used.

Copyright-paperwork-exempt: yes
---
 lisp/erc/erc.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index cf422f1..a8f1478 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -2010,7 +2010,8 @@ Returns the buffer for the given server or channel."
                            (auth-source-search :host server
                                                :max 1
                                                :user nick
-                                               :port port
+                                               ;; secrets.el wouldn’t accept a number
+                                               :port (if (numberp port) (number-to-string port) port)
                                                :require '(:secret)))
                       :secret)))
                 (if (functionp secret)
--
2.4.0