Remove extra whitespace.
Add support for setting coresize from sysconfig.

Add support for using this if it is defined by the administrator
in the /etc/sysconfig/varnish file.

From way back we've had a commented-out DAEMON_COREFILE_LIMIT in
our /etc/sysconfig/varnish file, which wasn't referenced anywhere.

Suggested by: gaoyongwei/itxx00 on github.