Fix problem with scripts not receiving a SIGPIPE when client drops

the connection (e.g., when user presses Stop).  We now stop
trying to send a message body immediately after an error from write.

Submitted by: Roy Fielding (with help from Nathan Kurz, PR#335)
Reviewed by: Dean Gaudet, Randy Terbush, Chuck Murcko


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@78028 13f79535-47bb-0310-9956-ffa450edef68