Fix loading data from snapshopt for alltypesagg table.

The alltypesagg table was not loaded correctly from a snapshot file due
to a missing ALTER TABLE statement, thereby causing some tests to fail.

Change-Id: I74066a99529f24fc268bb5779d3fb64fbd4f66b9
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3248
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Tested-by: jenkins