pgsql: Suppress volatile-related warning seen in some compilers.

Suppress volatile-related warning seen in some compilers.

Antique versions of gcc complain about vars that are initialized outside
PG_TRY and then modified within it. Rather than marking the var volatile,
expend one more line of code.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/1f115d98b984c80e635392aed10cc6185d1f8f4b

Modified Files
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src/pl/plpgsql/src/pl_handler.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)