Fix possible issues in skin/skin_path config handling (#1490125)

Conflicts:

	program/lib/Roundcube/rcube_plugin.php

CHANGELOG

@@ -13,6 +13,7 @@ CHANGELOG Roundcube Webmail
 - Fix handling of UNKNOWN-CTE response, try do decode content client-side (#1490046)
 - Fix bug where creating subfolders in shared folders wasn't possible without ACL extension (#1490113)
 - Fix reply scrolling issue with text mode and start message below the quote (#1490114)
+- Fix possible issues in skin/skin_path config handling (#1490125)
 
 RELEASE 1.0.3
 -------------

program/include/rcmail_output_html.php

@@ -168,6 +168,8 @@ class rcmail_output_html extends rcmail_output
             $valid = !$skin;
         }
 
+        $skin_path = rtrim($skin_path, '/');
+
         $this->config->set('skin_path', $skin_path);
         $this->base_path = $skin_path;