Use SA_RESETHAND or SA_ONESHOT when installing the coredump handlers.

In particular the handlers could trigger themselves into an infinite
loop if RLimitMem was used with a small amount of memory -- too small
for the signal stack frame to be set up.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@80264 13f79535-47bb-0310-9956-ffa450edef68