THRIFT-4805: Suppress excessive logging of SASL TTransportExceptions in case of END_OF_FILE

Two fixes here:

1. Additional logic to properly catch and handle TTransportException.
   Currently, T(SASL)TransportException gets caught and handled in
   the wrong catch-block.
2. The fix for THRIFT-3769 mutes _all_ TTransportExceptions in TThreadPoolServer.
   This might mute legitimate failures. The intent of THRIFT-3769 (and
   THRIFT-2268) was to mute the noise caused by TTransportException.END_OF_FILE.
   This commit lets legitimate failures to be bubbled upwards.