pgsql-server: Arrange to preallocate all required space for the buffer

Log Message:
-----------
Arrange to preallocate all required space for the buffer and FSM hash
tables in shared memory.  This ensures that overflow of the lock table
creates no long-lasting problems.  Per discussion with Merlin Moncure.

Modified Files:
--------------
    pgsql-server/src/backend/storage/freespace:
        freespace.c (r1.34 -> r1.35)

(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/storage/freespace/freespace.c.diff?r1=1.34&r2=1.35)
    pgsql-server/src/backend/storage/ipc:
        shmem.c (r1.80 -> r1.81)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/storage/ipc/shmem.c.diff?r1=1.80&r2=1.81)
    pgsql-server/src/backend/storage/lmgr:
        lock.c (r1.140 -> r1.141)

(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/storage/lmgr/lock.c.diff?r1=1.140&r2=1.141)
    pgsql-server/src/backend/utils/hash:
        dynahash.c (r1.53 -> r1.54)

(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/utils/hash/dynahash.c.diff?r1=1.53&r2=1.54)
    pgsql-server/src/include/storage:
        shmem.h (r1.42 -> r1.43)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/include/storage/shmem.h.diff?r1=1.42&r2=1.43)
    pgsql-server/src/include/utils:
        hsearch.h (r1.32 -> r1.33)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/include/utils/hsearch.h.diff?r1=1.32&r2=1.33)