In case one of the pre_connection hooks causes the hook run to stop by an error

In case one of the pre_connection hooks causes the hook run to stop by an error
the pre_connection hook of the core module maybe did not run
(it is APR_HOOK_REALLY_LAST) and hence we missed to

- Put the socket in c->conn_config
- Setup core output and input filters
- Set socket options and timeouts

For calls of ap_run_pre_connection where this matters create a wrapper named
ap_pre_connection that ensures that this happens.

* include/ap_mmn.h: Bump minor version as we added new ap_pre_connection
  function.

* include/http_connection.h: Declare ap_pre_connection prototype.

* server/connection.c: Make use of ap_pre_connection in ap_process_connection.

* server/core.c: Implement ap_pre_connection.

* server/mpm/event/event.c: Make use of ap_pre_connection.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1893497 13f79535-47bb-0310-9956-ffa450edef68