Use unix.ByteSliceToString in osVersionFreebsd and osVersionLinux to
convert the Utsname.Release []byte field to string.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
As already done in osVersionFreebsd. This will allow to use the Utsname
fields as []byte for easier conversion to string.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>