FW-262. OpenMoteCC2538 leds.

Changed behavior of leds for OpenMoteCC2538: green -> radio, orange -> sync (compliance with TelosB, with orange led substituting the TelosB blue one). Led yellow (debug) is turned off and disabled in 6top.
Hmm, I thought one of the goals at the plugfest was to see the LEDs blinking. Could you please remove thise `#ifdef` statements?