[BUGFIX] Livesearch does not find all pages

If you are a BE user with various mount points (no admin), live search
does not find all pages.

Change-Id: Ie4c9c41f65d8a84722fa3847921912c7fb5a18f1
Resolves: #29086
Releases: 4.5, 4.6
Reviewed-on: http://review.typo3.org/4460
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe
Reviewed-by: Susanne Moog
Tested-by: Susanne Moog