unit test fixup

plugins/inputs/prometheus/parser_test.go

@@ -111,7 +111,7 @@ func TestParseValidPrometheus(t *testing.T) {
 		"gauge": float64(1),
 	}, metrics[0].Fields())
 	assert.Equal(t, map[string]string{
-		"osVersion":        "CentOS\\ Linux\\ 7\\ (Core)",
+		"osVersion":        "CentOS Linux 7 (Core)",
 		"dockerVersion":    "1.8.2",
 		"kernelVersion":    "3.10.0-229.20.1.el7.x86_64",
 		"cadvisorRevision": "",