pgsql: pg_upgrade: Remove converter plugin facility.

pg_upgrade: Remove converter plugin facility.

We've not found a use for this so far, and the current need, which
is to convert the visibility map to a new format, does not suit the
existing design anyway. So just rip it out.

Author: Masahiko Sawada, slightly revised by me.
Discussion: 20160215211313(dot)GB31273(at)momjian(dot)us

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/6f56b41ac0cd7092b91834da02e70514d28b8edb

Modified Files
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src/bin/pg_upgrade/Makefile | 2 +-
src/bin/pg_upgrade/check.c | 2 -
src/bin/pg_upgrade/file.c | 77 ++----------------
src/bin/pg_upgrade/page.c | 164 ---------------------------------------
src/bin/pg_upgrade/pg_upgrade.c | 2 -
src/bin/pg_upgrade/pg_upgrade.h | 37 +--------
src/bin/pg_upgrade/relfilenode.c | 64 +++------------
7 files changed, 18 insertions(+), 330 deletions(-)