pgsql: Check return value of strdup() in libpq connection option parsin

Check return value of strdup() in libpq connection option parsing.

An out-of-memory in most of these would lead to strange behavior, like
connecting to a different database than intended, but some would lead to
an outright segfault.

Alex Shulgin and me. Backpatch to all supported versions.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/30bf4689a96cd283af33edcdd6b7210df3f20cd8

Modified Files
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src/interfaces/libpq/fe-connect.c |  132 +++++++++++++++++++++++++++++++------
1 file changed, 113 insertions(+), 19 deletions(-)