Обсуждение: pgsql: In pg_upgrade, document that link mode has to have data director

In pg_upgrade, document that link mode has to have data directories on
the same file system, and that authentication should lock out normal
users.

Per suggestsion from #postgresql irc channel.

Backpatch to 9.1.

Branch
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REL9_1_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/6e66d2e424d82978e452ace850ad80af78475043

Modified Files
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doc/src/sgml/pgupgrade.sgml |   11 +++++++----
1 files changed, 7 insertions(+), 4 deletions(-)