pgsql: Allow definition of lock mode for custom reloptions

Allow definition of lock mode for custom reloptions

Relation options can define a lock mode other than AccessExclusiveMode
since 47167b7, but modules defining custom relation options did not
really have a way to enforce that.  Correct that by extending the
current API set so as modules can define a custom lock mode.

Author: Michael Paquier
Reviewed-by: Kuntal Ghosh
Discussion: https://postgr.es/m/20190920013831.GD1844@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/69f94108079d70093b59096a3ae0ad82c842b4c0

Modified Files
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contrib/bloom/blutils.c                |  6 ++++--
src/backend/access/common/reloptions.c | 28 ++++++++++++----------------
src/include/access/reloptions.h        | 11 +++++++----
3 files changed, 23 insertions(+), 22 deletions(-)