pgsql: Check retain_dead_tuples for ALTER SUBSCRIPTION ... SERVER.

Check retain_dead_tuples for ALTER SUBSCRIPTION ... SERVER.

Previously, the subscription setting retain_dead_tuples didn't cause
ALTER SUBSCRIPTION ... SERVER to check the publisher. And if the
publisher was checked for some other reason, then it would use the old
conninfo.

Fix ALTER SUBSCRIPTION ... SERVER to always check the publisher when
retain_dead_tuples is set, and to use the new connection info, like
ALTER SUBSCRIPTION ... CONNECTION.

Reviewed-by: Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>
Discussion: https://postgr.es/m/f13a8e29410bbbf9999290f2c04513a8884fa51c.camel@j-davis.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/8eba2edb80102ac7d16c0335caca62e11adc8072

Modified Files
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src/backend/commands/subscriptioncmds.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)