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>