In the in-tree barman-cloud implementation, the check for an empty WAL
archive is performed both immediately after the restore process and when the
first WAL file is archived.
Previously, the plugin-based implementation only performed this check after
restore, skipping it during archiving of the first WAL. This patch restores
parity with the in-tree behavior by ensuring the check is also performed
during WAL archiving.
Closes: #457
Signed-off-by: Leonardo Cecchi <leonardo.cecchi@enterprisedb.com>
