pgsql: Fix psql describe commands' handling of ACL columns for old serv

Fix psql describe commands' handling of ACL columns for old servers.

Commit d1379ebf4 carelessly broke printACLColumn for pre-9.4 servers,
by using the cardinality() function which we introduced in 9.4.
We expect psql's describe-related commands to work back to 9.2, so
this is bad. Use the longstanding array_length() function instead.

Per report from Christoph Berg. Back-patch to v17.

Discussion: /messages/by-id/ZvLXYglRS6hMMhtr@msg.df7cb.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/1591b38d17c55015403f6e3c9461538ffcf704e7

Modified Files
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src/bin/psql/describe.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)