pgsql: Fix copy-paste bug in 12f3867f553 triggering an assert after a w

Fix copy-paste bug in 12f3867f553 triggering an assert after a write error

The same condition accidentally was copied to both branches. Manual testing
confirms that otherwise the error recovery path works fine.

Found while reviewing the logical-decoding-on-standby patch.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/21d7c05a5cf7637cbdf2739006936bb9d279d505

Modified Files
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src/backend/storage/buffer/bufmgr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)