Use printf rather than echo when writing default.vcl

echo -e isn't in POSIX so it's not supported by all shells.  Use
printf instead of echo to work around this.

etc/Makefile.am

@@ -6,7 +6,7 @@ DISTCLEANFILES = default.vcl
 dist_varnishconf_DATA = default.vcl
 
 default.vcl:	$(top_srcdir)/bin/varnishd/default.vcl
-	@echo -e "This is a basic VCL configuration file for varnish.  See the vcl(7)\n\
+	@printf "This is a basic VCL configuration file for varnish.  See the vcl(7)\n\
 man page for details on VCL syntax and semantics.\n\
 \n\
 Default backend definition.  Set this to point to your content\n\