DragonFlyBSD

Noticed this was incorrect when writing some os-detection userland code. Took the liberty to add some notes about the os flat number versioning scheme.

before : man 3 sysctl

     KERN_OSRELDATE
             The system release date in YYYYMM format (January 1996 is encoded
             as 199601).

     KERN_OSREV
             The system revision string.

after : man 3 sysctl

     KERN_OSRELDATE
             The same as ‘KERN_OSREV’.

     KERN_OSREV
             The system revision number in base-10 format Mmmmpp, representing
             the following components:

                   Code    Component
                   M       major
                   mmm     minor
                   pp      patch

             The minor component is an even-number for release and odd-number
             for development branches.