pgsql: Fix BF failure in commit 93db6cbda0.

Fix BF failure in commit 93db6cbda0.

The code to match the required LOG in the test was not robust enough to
match it. It was using a very specific format to search the required
message which doesn't work when one uses log_error_verbosity = verbose.

Author: Hou Zhijie
Discussion: https://postgr.es/m/CAA4eK1KcQSk7wzC7Zfrth9OhrjW2HvxL4tKgU42qqH7p6jn+FA@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/d13ff82319ccaacb04d77b77a010ea7a1717564f

Modified Files
--------------
src/test/recovery/t/040_standby_failover_slots_sync.pl | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)