cpuburn-neon: fix packaging to use a date as version and valid sources

* The package were not versioning the sources as the files had no
   version on its name. We workaround it mangling the DL_DIR;

 * We now dynamically check if the machine has or not neon feature and
   set COMPATIBLE_MACHINE.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
Signed-off-by: Eric Bénard <eric@eukrea.com>