From Fedora Project Wiki

Packages with initscripts must put any initscripts into /etc/rc.d/init.d.

In the past, some packages were putting files in /etc/init.d as well as /etc/rc.d/init.d. Without requiring a specific location, it makes it more difficult to use yum install against the initscript filename and path. Since /etc/init.d is the symlink (and because the Filesystem Hierarchy Standard does not mandate a location), the full directory is required.