Don't allocate storage for partitioned tables.

Don't allocate storage for partitioned tables.

Also, don't allow setting reloptions on them, since that would have no
effect given the lack of storage.  The patch does this by introducing
a new reloption kind for which there are currently no reloptions -- we
might have some in the future -- so it adjusts parseRelOptions to
handle that case correctly.

Bumped catversion.  System catalogs that contained reloptions for
partitioned tables are no longer valid; plus, there are now fewer
physical files on disk, which is not technically a catalog change but
still a good reason to re-initdb.

Amit Langote, reviewed by Maksim Milyutin and Kyotaro Horiguchi and
revised a bit by me.

Discussion: http://postgr.es/m/20170331.173326.212311140.horiguchi.kyotaro@lab.ntt.co.jp