internal: add baidu.com to the broken auth list

Change-Id: I17fe6f8fce63c7d68975450ba106698533c392d9
Reviewed-on: https://go-review.googlesource.com/19742
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

internal/token.go

@@ -105,6 +105,7 @@ var brokenAuthHeaderProviders = []string{
 	"https://oauth.sandbox.trainingpeaks.com/",
 	"https://oauth.trainingpeaks.com/",
 	"https://oauth.vk.com/",
+	"https://openapi.baidu.com/",
 	"https://slack.com/",
 	"https://test-sandbox.auth.corp.google.com",
 	"https://test.salesforce.com/",