refs #74448, fix base64 decode defect
refs #74448, fix base64 decode defect

* a valid base64 string ends with "=" only (e.g. "xxx..xx=a" is invalid),
mordor should recognise this.

Change-Id: Ibaac0ec3dda7988cbccae69d71319f89a057e89e
Signed-off-by: Eric Wang <6840854f89a162593efc1aa9a3c4fd0f1c7863e0@mozy.com>
Reviewed-on: https://gerrit.dechocorp.com/27777
Reviewed-by: Jenkins <49695b0f9c673fd73dab0ff3f84b5ced9302cc6a@mozy.com>
Reviewed-by: Kevin Cai <7771192b74080b0349ce1991a9eaaeec64bf9e00@vmware.com>

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