when this module's resolver calls were apr-ized recently we removed

the include of specific system header files; this left the opportunity
for htons() to be undefined...  do something explicit for htons() so
we don't have to worry about what apr_network_io.h brings with it


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@92091 13f79535-47bb-0310-9956-ffa450edef68