Drop ExecStartPre

Fixes startup if vcl_dir was specified in DAEMON_OPTS.
Reported by Gauthier Delacroix. Discussed with ssm on irc.

redhat/varnish.service

@@ -27,7 +27,6 @@ EnvironmentFile=/etc/varnish/varnish.params
 Type=forking
 PIDFile=/var/run/varnish.pid
 PrivateTmp=true
-ExecStartPre=/usr/sbin/varnishd -C -f $VARNISH_VCL_CONF
 ExecStart=/usr/sbin/varnishd \
 	-P /var/run/varnish.pid \
 	-f $VARNISH_VCL_CONF \