pgsql: Adjust pg_upgrade query so toast tables related to system catalo

Adjust pg_upgrade query so toast tables related to system catalog schema
entries are not dumped. This fixes an error caused by
droping/recreating the information_schema, but other failures were also
possible.

Backpatch to 9.2.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/ac96b851ec44cbf63bf0b231e813c0ab4af08d6b

Modified Files
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contrib/pg_upgrade/info.c | 51 +++++++++++++++++++++++++++++++++-----------
1 files changed, 38 insertions(+), 13 deletions(-)