Fix spelling on information_schema.table_constraints.is_deferrable
column to match SQL standard.
Throw an exception if you try to GROUP BY ROLLUP
merge tjoneslo: Fix spelling on information_schema.table_constraints.is_deferrable

Merge pull request #1352 from tjoneslo/sql-layer/IS_table-constraints-is-deferrable
https://github.com/FoundationDB/sql-layer/pull/1352
merge ScottDugas: Throw an exception if you try to GROUP BY ROLLUP

Merge pull request #1353 from ScottDugas/sql-layer/unsupported-group-by-rollup
https://github.com/FoundationDB/sql-layer/pull/1353