In the source code of cephfs there is no reference to it anymore,
but it's still in the man page. Leave it there for now, but make
it more clear that it is deprecated and unsupported.
Keeping the generated files in version control lets us
support builds from scratch without requiring the full
documentation toolchain to be installed.
The files were just copied over from build-doc/output/man,
after a ./admin/build-doc call. When redoing this, also
take care to remove any roff output if a file was removed
from doc/man, and update Makefile.am.
Signed-off-by: Tommi Virtanen <tommi.virtanen@dreamhost.com>