Fix SMTP AUTH in smtp_forward/proxy and add docs

docs/plugins/queue/smtp_forward.md

@@ -45,6 +45,18 @@ Configuration

    Enable TLS with the forward host (if supported)

  * auth\_type=[plain|login]

    Enable PLAIN or LOGIN SMTP AUTH.  This is required to enable AUTH.

   * auth\_user=USERNAME

    SMTP AUTH username to use.

   * auth\_pass=PASSWORD

    SMTP AUTH password to use.

# Per-Domain Configuration

More specific forward routes for domains can be defined. More specific routes

docs/plugins/queue/smtp_proxy.md

@@ -46,3 +46,15 @@ Configuration
 
    Enable TLS with the forward host (if supported)

  * auth\_type=[plain|login]

    Enable PLAIN or LOGIN SMTP AUTH.  This is required to enable AUTH.

   * auth\_user=USERNAME

    SMTP AUTH username to use.

   * auth\_pass=PASSWORD

    SMTP AUTH password to use.

smtp_client.js

@@ -283,6 +283,15 @@ exports.get_client = function (server, callback, port, host, connect_timeout, po
// smtp_forward have in common.
exports.get_client_plugin = function (plugin, connection, config, callback) {
    var c = config;
    // Merge in authentication settings from smtp_forward/proxy.ini if present
    // FIXME: config.auth could be changed when API isn't frozen
    if (c.auth_type || c.auth_user || c.auth_pass) {
        c.auth = {
            type: c.auth_type,
            user: c.auth_user,
            pass: c.auth_pass
        }
    }
    var pool = exports.get_pool(connection.server, c.port, c.host,
                                c.connect_timeout, c.timeout, c.max_connections);
    pool.acquire(function (err, smtp_client) {