pgsql: pg_upgrade: Make format strings consistent

pg_upgrade: Make format strings consistent

The backport of commit f295494d338 introduced a format string using
%m. This is not wrong, since those have been supported since commit
d6c55de1f99a, but only commit 2c8118ee5d9 later introduced their use
in this file. This use introduces a gratuitously different
translatable string and also makes it inconsistent with the rest of
the file. To avoid that, switch this back to the old-style strerror()
route in the appropriate backbranches

Branch
------
REL_14_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/ed2bb0cdda7764a95d6e1e4019417a7857b6f002

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