Fix inserting elements at the head and tail of a ring when the ring is

empty. Avoiding referring to the element type in the macros resulted
in some double dereferences that did the wrong thing.
Reported by:	Jeff Trawick


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@86184 13f79535-47bb-0310-9956-ffa450edef68