Обсуждение: pgsql: Fix lockmode initialization for custom relation options

Fix lockmode initialization for custom relation options

The code was enforcing AccessExclusiveLock for all custom relation
options, which is incorrect as the APIs allow a custom lock level to be
set.

While on it, fix a couple of inconsistencies in the tests and the README
of dummy_index_am.

Oversights in commit 773df88.

Discussion: https://postgr.es/m/20190925234152.GA2115@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/fbfa5664882c9b61428266e6fb0d48b0147c421a

Modified Files
--------------
src/backend/access/common/reloptions.c                  | 7 -------
src/test/modules/dummy_index_am/README                  | 1 +
src/test/modules/dummy_index_am/expected/reloptions.out | 4 +++-
src/test/modules/dummy_index_am/sql/reloptions.sql      | 1 +
4 files changed, 5 insertions(+), 8 deletions(-)