docs: re-add instructions on setting wal_level for rsync use
This step was erroneously removed four days ago by me.
Reported-by: Magnus via IM
Backpatch-through: 9.5
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/00210e3fb974ff2b9affc4d8f3b29f9cb3645a60
Modified Files
--------------
doc/src/sgml/ref/pgupgrade.sgml | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)