pgsql-server: Fix pg_dumpall to use double-quote for Win32 arguments.

Log Message:
-----------
Fix pg_dumpall to use double-quote for Win32 arguments.

Luiz K. Matsumura

Modified Files:
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pgsql-server/src/bin/pg_dump:
pg_dumpall.c (r1.51 -> r1.52)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/bin/pg_dump/pg_dumpall.c.diff?r1=1.51&r2=1.52)