Ignore plugin_manager plugin.

Allow packagist.

.gitignore

@@ -6,6 +6,7 @@ plugins/*/config.inc.php
 
 # this is for the sample plugin (via composer)
 plugins/rcsample
+plugins/plugin_manager
 
 # composer-related
 composer.json

composer.json-dist

@@ -3,9 +3,6 @@
     "description": "The Roundcube Webmail suite",
     "license": "GPL-3.0",
     "repositories": [
-        {
-            "packagist": false
-        },
         {
             "type": "composer",
             "url": "http://plugins.roundcube.net/"