fix incorrect recover for hidden debug output of basic auth
fix incorrect recover for hidden debug output of basic auth

* While doing debug log output, basic auth info will be temporarily
  replaced with "<hidden>" for protecting sensitive info.
* The value is not correctly recovered when the base64 param in original
  request is empty in a bad request.

Change-Id: I07a6e1578439d16ffd4e6ee3a9eae73dfdfca0f9
Signed-off-by: Kevin Cai <c4f49ef5a44534d46de426dda18a118a2ca4debf@mozy.com>
Reviewed-on: https://gerrit.dechocorp.com/57155
Reviewed-by: Jenkins <49695b0f9c673fd73dab0ff3f84b5ced9302cc6a@mozy.com>
Reviewed-by: Andrew Skowronski <96924f7a4dbe24093bb2da18f50a76703cb4a362@mozy.com>

adfin/mordor,mtanski/mordor,adfin/mordor,mtanski/mordor,adfin/mordor,mozy/mordor,mozy/mordor,mtanski/mordor,mozy/mordor