[Hibernate] MSSQL and sequences test

[Max R. A. <ma...@eo...>]

I've just submitted a small patch to the tests so MSSQL can run the
MasterDetailTest.

Changes are:

1. Use native instead of the single usage of "sequences"
2. Avoid the usage of "key" as a column as it is a reservered keyword.

ad. 2 shouldn't harm anyone as it is just a simple rename, that actually
works as an additional test of the column attribute.
ad. 1. is "worse" as this was/are the only place in the unittst that
sequences are used, but I think it is more important to
have MSSQL complete on the MasterDetailTest which includes 10 other tests
that is not otherwise executed.

What about either:

- creating a separate test for the sequences
or/and
- create an id-generator that is called something like "sequenceOrnative"
which will choose sequence if that is availabe
in the current dialect and if not choose native ? (and maybe make this more
general - like an ordered list of id-generators which
could handle it in a more general way)

/max