pgsql: Reduce the default for max_worker_processes back to 8.

Reduce the default for max_worker_processes back to 8.

Commit b460f5d6693103076dc554aa7cbb96e1e53074f9 -- at my suggestion --
increased the default value of max_worker_processes from 8 to 16, on
the theory that this would be harmless and convenient for users.
Unfortunately, this caused some buildfarm machines with low connection
limits to start failing, so apparently it's not harmless after all.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/2b959d4957ff47c77b2518dcddbf3aa126a1593c

Modified Files
--------------
doc/src/sgml/config.sgml | 2 +-
src/backend/utils/init/globals.c | 2 +-
src/backend/utils/misc/guc.c | 2 +-
src/backend/utils/misc/postgresql.conf.sample | 2 +-
src/bin/pg_resetxlog/pg_resetxlog.c | 4 ++--
5 files changed, 6 insertions(+), 6 deletions(-)