pgsql: Suppress possibly-uninitialized-variable warnings from gcc 4.5.

Suppress possibly-uninitialized-variable warnings from gcc 4.5.

It appears that gcc 4.5 can issue such warnings for whole structs, not
just scalar variables as in the past. Refactor some pg_dump code slightly
so that the OutputContext local variables are always initialized, even
if they won't be used. It's cheap enough to not be worth worrying about.

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=e2627258c3cc43b8b00c5c29c35933a33259e718

Modified Files
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src/bin/pg_dump/pg_backup_archiver.c | 44 ++++++++++++++++++++++-----------
src/bin/pg_dump/pg_backup_archiver.h | 6 ----
2 files changed, 29 insertions(+), 21 deletions(-)