pgsql: postgres_fdw and dblink should check if backend has MyProcPort

postgres_fdw and dblink should check if backend has MyProcPort

before checking ->has_scram_keys. MyProcPort is NULL in background
workers. So this could crash for example if a background worker
accessed a suitable configured foreign table.

Author: Alexander Pyhalov <a(dot)pyhalov(at)postgrespro(dot)ru>
Reviewed-by: Peter Eisentraut <peter(at)eisentraut(dot)org>
Reviewed-by: Matheus Alcantara <matheusssilv97(at)gmail(dot)com>
Discussion: https://www.postgresql.org/message-id/flat/27b29a35-9b96-46a9-bc1a-914140869dac%40gmail.com

Branch
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REL_18_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/762fed90bfee248ca090a96fe883e063ba035088

Modified Files
--------------
contrib/dblink/dblink.c | 8 ++++----
contrib/postgres_fdw/connection.c | 8 ++++----
2 files changed, 8 insertions(+), 8 deletions(-)