pgsql: Fix some unportable constructs in parallel pg_dump code.

Fix some unportable constructs in parallel pg_dump code.

Didn't compile on semi-obsolete gcc, and probably not on not-gcc-at-all
either.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/846681fdd574548d4f430f2ff7ab44d77b4c79fe

Modified Files
--------------
src/bin/pg_dump/dumputils.h          |    3 +--
src/bin/pg_dump/parallel.h           |    6 ------
src/bin/pg_dump/pg_backup_archiver.h |   11 ++++++++---
3 files changed, 9 insertions(+), 11 deletions(-)