[CLEANUP] Tags are not translatable so remove l10n_mode

The title column in tas has l10n_mode set, but the
complete tag table is not translatable.

Remove the mode setting.

Change-Id: I5de5a0587afb5cc80d12e11b21fbb8b31919edb2
Reviewed-on: https://review.typo3.org/29621
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel