Merge r1294306 from trunk:

Initialize EC temporary key on server startup, as for DH and
RSA. This fixes a race condition that could lead to a crash with threaded
MPMs.

Submitted by: sf
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1308862 13f79535-47bb-0310-9956-ffa450edef68