Use new utils/version.c instead of backend/utils/init/magic.c.

src/backend/Makefile

src/backend/postmaster/postmaster.c

src/backend/utils/init/Makefile

src/backend/utils/init/postinit.c

src/bin/pg_version/Makefile

src/bin/pg_version/pg_version.c

src/include/miscadmin.h