Fix proper overwrite URL on CLI install

* regression from #7835

Steps

* having a my.config.php with a proper `overwrite.cli.url` and `htaccess.RewriteBase` set
* install with this
* before: short URLs where broken and you need to call `occ maintenance:update:htaccess` additionally to fix this
* after: occ install results in a proper htaccess like on stable13

Signed-off-by: Morris Jobke <hey@morrisjobke.de>