core: (dummy_connection): Destroy tmp pool and

return on connect() failure. Fixes small memory
leak for Unix MPMs in parent process if connect()
failed when waking up children.

Backport of r1300171 from trunk resp. r1301649 from 2.4.x.

Submitted by: jorton
Reviewed by: trawick, wrowe
Backported by: rjung


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1374537 13f79535-47bb-0310-9956-ffa450edef68