Error message editing in backend/storage.

src/backend/storage/buffer/buf_table.c

src/backend/storage/buffer/bufmgr.c

src/backend/storage/buffer/freelist.c

src/backend/storage/buffer/localbuf.c

src/backend/storage/file/buffile.c

src/backend/storage/file/fd.c

src/backend/storage/freespace/freespace.c

src/backend/storage/ipc/README

src/backend/storage/ipc/ipc.c

src/backend/storage/ipc/ipci.c

src/backend/storage/ipc/shmem.c

src/backend/storage/ipc/sinval.c

src/backend/storage/ipc/sinvaladt.c

src/backend/storage/large_object/inv_api.c

src/backend/storage/lmgr/deadlock.c

src/backend/storage/lmgr/lmgr.c

src/backend/storage/lmgr/lock.c

src/backend/storage/lmgr/lwlock.c

src/backend/storage/lmgr/proc.c

src/backend/storage/page/bufpage.c