middleware/{log,errors}: output everything to stdout (#684)

Limit the options in both errors and log middleware, just output to
stdout and let someone else (journald,docker) care about where to route
the logs. This removes syslog and logging to a file.

Fixes #573 #602

middleware/log/setup_test.go

@@ -45,7 +45,7 @@ func TestLogParse(t *testing.T) {
 			Format:     CombinedLogFormat,
 		}}},
 		{`log example.org. log.txt
-			  log example.net accesslog.txt {combined}`, false, []Rule{{
+		log example.net accesslog.txt {combined}`, false, []Rule{{
 			NameScope:  "example.org.",
 			OutputFile: "log.txt",
 			Format:     DefaultLogFormat,