Update RedHat / CentOS PHP CLI package name

On RedHat and CentOS systems the PHP CLI binary is provided by the `php-cli` package:

http://pkgs.org/search/?keyword=php-cli&search_on=name&distro=82&exact=1

Also removed `CentOS` from the `$::osfamily` case check as it isn't actually an OS family:

https://github.com/puppetlabs/facter/blob/master/lib/facter/osfamily.rb#L19-L20