pgsql: Note explicitly that hash indexes are also not replicated becaus

Note explicitly that hash indexes are also not replicated because they're not
WAL-logged. Make the notice about the lack of WAL-logging more visible by
making it a <caution>. Also remove the false statement from hot standby
caveats section that hash indexes are not used during hot standby.

Branch
------
REL9_0_STABLE

Details
-------
http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=b887f7b3526627d22d01d0cdb74a21ead08934a7

Modified Files
--------------
doc/src/sgml/high-availability.sgml |    3 +--
doc/src/sgml/indices.sgml           |    9 +++++----
2 files changed, 6 insertions(+), 6 deletions(-)