[CLEANUP] Remove unused code from old backend

Prior to TYPO3 CMS 4.5 there were still some
variables which are not used anymore since then.

The menuReset() function does not exist anymore
as well as the CSS class "navFrameHL".

Releases: master
Resolves: #62033
Change-Id: Ie7bda9d4e3d6f2090548d133768543236112b2cb
Reviewed-on: http://review.typo3.org/33162
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>