Document IPv6 support in rpc.mountd and exportfs, and clarify existing
language in the man page.
Clean up: Use bold consistently for program names, and italics
consistently for file names. Use "rpc.mountd" consistently as the
name of the mountd daemon.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Steve Dickson <steved@redhat.com>