pgbulkload - pgbulkload: Add checks for shmem id conflictions.

Log Message:
-----------
Add checks for shmem id conflictions.

Modified Files:
--------------
    pgbulkload/bin/pgut:
        pgut.h (r1.5 -> r1.6)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbulkload/pgbulkload/bin/pgut/pgut.h?r1=1.5&r2=1.6)
    pgbulkload/include:
        reader.h (r1.3 -> r1.4)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbulkload/pgbulkload/include/reader.h?r1=1.3&r2=1.4)
    pgbulkload/lib:
        reader.c (r1.4 -> r1.5)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbulkload/pgbulkload/lib/reader.c?r1=1.4&r2=1.5)
        source.c (r1.1 -> r1.2)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbulkload/pgbulkload/lib/source.c?r1=1.1&r2=1.2)
        writer_parallel.c (r1.1 -> r1.2)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbulkload/pgbulkload/lib/writer_parallel.c?r1=1.1&r2=1.2)
    pgbulkload/lib/pgut:
        pgut-ipc.c (r1.1 -> r1.2)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbulkload/pgbulkload/lib/pgut/pgut-ipc.c?r1=1.1&r2=1.2)
        pgut-ipc.h (r1.1 -> r1.2)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbulkload/pgbulkload/lib/pgut/pgut-ipc.h?r1=1.1&r2=1.2)