pgsql: Back-patch "Only quote libpq connection string values that need

Back-patch "Only quote libpq connection string values that need quoting."

Back-patch commit 2953cd6d17210935098c803c52c6df5b12a725b9 and certain
runPgDump() bits of 3dee636e0404885d07885d41c0d70e50c784f324 to 9.2 and
9.1.  This synchronizes their doConnStrQuoting() implementations with
later releases.  Subsequent security patches will modify that function.

Security: CVE-2016-5424

Branch
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REL9_1_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/c761c9fee082623777466e6a5841056960fc006c

Modified Files
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src/bin/pg_dump/pg_dumpall.c | 48 +++++++++++++++++++++++++++++++++-----------
1 file changed, 36 insertions(+), 12 deletions(-)