参考資料
$ find -type f -exec grep --color -Hn php {} \; ./conf.d/php.conf:6:LoadModule php5_module modules/libphp5.so ./conf.d/php.conf:11:AddHandler php5-script .php ./conf.d/php.conf:12:AddType text/html .php ./conf.d/php.conf:18:DirectoryIndex index.php ./conf.d/ssl.conf:208:<Files ~ "\.(cgi|shtml|phtml|php3?)$"> ./conf/httpd.conf:383:DirectoryIndex index.php index.rb index.html index.html.var
PHP: Apache 2.x (Unixシステム用) - Manual
Cannot load /etc/httpd/modules/libphp5.so
インストール漏れかと思いきやモジュールそのものを作り忘れた