pgsql: Fix unportable printf format introduced in commit 9290ad198.

Fix unportable printf format introduced in commit 9290ad198.

"%ld" is not an acceptable format spec for int64 variables, though
it accidentally works on most non-Windows 64-bit platforms. Follow
the lead of commit 6a1cd8b92, and use "%lld" with an explicit cast
to long long. Per buildfarm.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/5883f5fe27d7b52c812dd0f8cbda67373a14c451

Modified Files
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src/backend/replication/walsender.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)