Update roundcube to 1.2.4.

CHANGELOG Roundcube Webmail
===========================

RELEASE 1.2.4
-------------
- Managesieve: Fix handling of scripts with nested rules (#5540)
- Managesieve: Fix parser issue with empty lines between comments (#5657)
- Managesieve: Fix possible defect in handling \r\n in scripts (#5685)
- Fix variable substitution in ldap host for some use-cases,
  e.g. new_user_identity (#5544)
- Fix adding images to new identity signatures
- Fix rsync error handling in installto.sh script (#5562)
- Fix some advanced search issues with multiple addressbooks (#5572)
- Fix so group/addressbook selection is retained on page refresh
- Fix bug where image data URIs in css style were treated as evil/remote in
  mail preview (#5580)
- Fix bug where external content in src attribute of input/video tags was not
  secured (#5583)
- Fix PHP error on update of a contact with multiple email addresses when
  using PHP 7.1 (#5587)
- Fix bug where mail content frame couldn't be reset in some corner cases
  (#5608)
- Fix bug where some classic skin images were not displayed in IE/Edge (#5614)
- Fix bug where signature couldn't be added above the quote in Firefox 51
  (#5628)
- Fix regression where groups with email address were resolved to its members'
  addresses
- Fix update of group name in the contacts list header on group rename (#5648)
- Add rewrite rule to disable access to /vendor/bin folder in .htaccess (#5630)
- Fix bug where it was too easy accidentally move a folder when using the
  subscription checkbox (#5655)
- Fix XSS issue in handling of a style tag inside of an svg element

(taca)