pgsql: Add a hack so that get_type_io_data() can work from bootstrap.c's

Log Message:
-----------
Add a hack so that get_type_io_data() can work from bootstrap.c's
internal TypInfo table in bootstrap mode.  This allows array_in and
array_out to be used during early bootstrap, which eliminates the
former obstacle to giving OUT parameters to built-in functions.

Modified Files:
--------------
    pgsql/src/backend/bootstrap:
        bootstrap.c (r1.223 -> r1.224)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/bootstrap/bootstrap.c.diff?r1=1.223&r2=1.224)
    pgsql/src/backend/utils/cache:
        lsyscache.c (r1.135 -> r1.136)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/cache/lsyscache.c.diff?r1=1.135&r2=1.136)
    pgsql/src/include/bootstrap:
        bootstrap.h (r1.42 -> r1.43)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/bootstrap/bootstrap.h.diff?r1=1.42&r2=1.43)