pgsql: Fix newly introduced 010_keep_recycled_wals.pl

Fix newly introduced 010_keep_recycled_wals.pl

It failed to set the archive_command as it desired because of a syntax
problem.  Oversight in commit 90bcc7c2db1d.

This bug doesn't cause the test to fail, because the test only checks
pg_rewind's output messages, not the actual outcome (and the outcome in
both cases is that the file is kept, not deleted).  But in either case
the message about the file being kept is there, so it's hard to get
excited about doing much more.

Reported-by: Antonin Houska <ah@cybertec.at>
Author: Alexander Kukushkin <cyberdemn@gmail.com>
Discussion: https://postgr.es/m/7822.1732167825@antos

Branch
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REL_16_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/50010c6f6c4d10e8d78d2d550bdaea461d0c83a9

Modified Files
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src/bin/pg_rewind/t/010_keep_recycled_wals.pl | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)