[BUGFIX] Escape dashes in regex character classes

Change-Id: I60aa96ec03451eb8dc0efb1eec33fdbe59482c17
Resolves: #61852
Reviewed-on: http://review.typo3.org/32966
Reviewed-by: Jesper Mathiasen <jekorma@gmail.com>
Tested-by: Jesper Mathiasen <jekorma@gmail.com>
Reviewed-by: Steffen Müller <typo3@t3node.com>
Tested-by: Steffen Müller <typo3@t3node.com>