Deleted the files in /private/etc/apache2/other/
The file that is in your /private/etc/apache2/other directory is your php5.conf file.

What's in your /private/etc/apache2/original/extra directory are sample httpd conf files to configure your apache server. 

I have made my untouched php5.conf file available for download.  Since I don't use the AMP stack on my Mac for any dev work, it should be the same one that gets installed with macOS.  It won't have any of the modifications/customizations yours had, if you made any.

Copy that file to the 'other' directory.  Make sure you se the correct owner and  permissions:

sudo chmod 444 /private/etc/apache2/other/php5.conf
sudo chown root:wheel /private/etc/apache2/other/php5.conf