pgsql: postgres_fdw: Teach IMPORT FOREIGN SCHEMA about partitioning.

postgres_fdw: Teach IMPORT FOREIGN SCHEMA about partitioning.

Don't import partitions.  Do import partitioned tables which are
not themselves partitions.

Report by Stephen Frost.  Design and patch by Michael Paquier,
reviewed by Amit Langote.  Documentation revised by me.

Discussion: http://postgr.es/m/20170309141531.GD9812@tamriel.snowman.net

Branch
------
master

Details
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http://git.postgresql.org/pg/commitdiff/f49bcd4ef3e9a75de210357a4d9bbe3e004db956

Modified Files
--------------
contrib/postgres_fdw/expected/postgres_fdw.out | 36 +++++++++++++++++++++++---
contrib/postgres_fdw/postgres_fdw.c            | 11 +++++++-
contrib/postgres_fdw/sql/postgres_fdw.sql      |  3 +++
doc/src/sgml/postgres-fdw.sgml                 | 10 +++++++
4 files changed, 55 insertions(+), 5 deletions(-)