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)