Add extra conf for Apache 2.4

Inside a conditional to affect only 2.4, set User, Group, and the
module config to load mpm_event.  This is normally done with the
default configuration files, but since this abbreviated conf bypasses
those, we must set them here.

Signed-off-by: Dan Mick <dan.mick@inktank.com>
tasks/rgw: get mpm_event frmo mods-available, not mods-enabled

Signed-off-by: Sage Weil <sage@redhat.com>
tasks/rgw: include mod_authz

As per http://www.webhostingtalk.com/showthread.php?t=1173594

Signed-off-by: Sage Weil <sage@redhat.com>