pgsql: Replace strdup() with pstrdup(), to avoid leaking memory.

Replace strdup() with pstrdup(), to avoid leaking memory.

It's been like this since the seg module was introduced, so backpatch to
8.2 which is the oldest supported version.

Branch
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REL8_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/1f57a2f4dd2f6033e28b0e1f04ef31d5f456793c

Modified Files
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contrib/seg/seg.c |    2 +-
1 files changed, 1 insertions(+), 1 deletions(-)