backport a union semun portablity fix from 2.1-dev (use unsigned short

instead of ushort)

Reviewed by:	jwoolley, dreid


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/APACHE_2_0_BRANCH@101782 13f79535-47bb-0310-9956-ffa450edef68