pgsql: Make psql use pg_table_size instead of pg_relation_size on 9.0+

Make psql use pg_table_size instead of pg_relation_size on 9.0+ servers.

Per discussion, pg_table_size() is a more helpful number than
pg_relation_size().

Bernd Helmle, reviewed by Susanne Ebrecht and me.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/cba9cd419270a9b7f442877e21685ac0de5730b3

Modified Files
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src/bin/psql/describe.c | 19 +++++++++++++++----
1 files changed, 15 insertions(+), 4 deletions(-)