Fixes and removal of obsolete code.

-- LP 1400556 'get tables in schema' is not supported on external
    hbase tables. An error  is now returned.
-- LP 1400553  Insert into external hbase tables in _ROW_ format must use
   column_create function and VALUES clause to create rows.
   An error is returned otherwise.
-- a bug with that prevented a boundary case when sequence increment value
   was one less than largeint max has been fixed.
-- error message to indicate what options can be used during alter sequence
   has been updated
-- create table as select  stmt now returns an error if running within a user
   transaction. This is the same behavior as other DDL operations.
   This will be
   removed once we have transaction support for DDL stmts.
-- create table as select now uses non-transactional 'upsert using load' to
   populate target table instead of transactional 'insert...select' stmt.
-- hive/test020 has been enabled. This tests for access to ORC files.
-- obsolete sidetree insert and NVT user load code has been removed.

Change-Id: I14d321deaa52321777acd1d8ca55420f1e973367
Merge "Fixes and removal of obsolete code."