HIVE-8246: HiveServer2 in http-kerberos mode is restrictive on client usernames (Vaibhav Gumashta reviewed by Thejas Nair)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/branch-0.14@1628053 13f79535-47bb-0310-9956-ffa450edef68