Back out check for unreferenced files.

doc/src/sgml/maintenance.sgml

src/backend/access/transam/xlog.c

src/backend/catalog/catalog.c

src/backend/commands/tablespace.c

src/backend/utils/adt/misc.c

src/backend/utils/init/Makefile

src/backend/utils/init/checkfiles.c

src/include/catalog/catalog.h

src/include/utils/flatfiles.h