pgsql: pg_upgrade: Handle hash index upgrades more smoothly.

pg_upgrade: Handle hash index upgrades more smoothly.

Mark any old hash indexes as invalid so that they don't get used, and
create a script to run REINDEX on all of them. Without this, we'd
still try to use any upgraded hash indexes, but it would fail.

Amit Kapila, reviewed by me. Per a suggestion from Tom Lane.

Discussion: http://postgr.es/m/CAA4eK1Jidtagm7Q81q-WoegOVgkotv0OxvHOjFxcvFRP4X=mSw@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a95410e2ec39b6776381fd01198dc57a063e8185

Modified Files
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src/bin/pg_upgrade/check.c | 17 +++++-
src/bin/pg_upgrade/pg_upgrade.h | 2 +
src/bin/pg_upgrade/version.c | 112 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 130 insertions(+), 1 deletion(-)