Go back to the FIFO scheduler for now, as we don't have time to shake out the RR scheduler changeover just yet.

Make the "default" scheduler a centralized definition so that changes are easier in future.

apps/systemlib/systemlib.h

@@ -50,6 +50,13 @@ __EXPORT int reboot(void);
 /** Sends SIGUSR1 to all processes */
 __EXPORT void killall(void);
 
+/** Default scheduler type */
+#if CONFIG_RR_INTERVAL > 0
+# define SCHED_DEFAULT	SCHED_RR
+#else
+# define SCHED_DEFAULT	SCHED_FIFO
+#endif
+
 /** Starts a task and performs any specific accounting, scheduler setup, etc. */
 __EXPORT int task_spawn(const char *name,
 			int priority,