HBase Thrift 1 server SPNEGO Improvements

HBase Thrift1 server has some issues when trying to use SPNEGO.

From mailing list:
http://mail-archives.apache.org/mod_mbox/hbase-user/201801.mbox/%3CCAJU9nmh5YtZ%2BmAQSLo91yKm8pRVzAPNLBU9vdVMCcxHRtRqgoA%40mail.gmail.com%3E

While setting up the HBase Thrift server with HTTP, there were a
significant amount of 401 errors where the HBase Thrift wasn't able to
handle the incoming Kerberos request. Documentation online is sparse when
it comes to setting up the principal/keytab for HTTP Kerberos.

I noticed that the HBase Thrift HTTP implementation was missing SPNEGO
principal/keytab like other Thrift based servers (HiveServer2). It looks
like HiveServer2 Thrift implementation and HBase Thrift v1 implementation
were very close to the same at one point. I made the following changes to
HBase Thrift v1 server implementation to make it work:

• add SPNEGO principal/keytab if in HTTP mode
• return 401 immediately if no authorization header instead of waiting for
  try/catch down in program flow