sched/sched_releasetcb.c: Fix an error handling case where a pthread start-up...

sched/sched_releasetcb.c:  Fix an error handling case where a pthread start-up fails early, before the task type has been saved in the TCB.  It is safer to use the sched_releasetcb() task type argument instead of relying on the task type in the TCB to be valid.  Reported by David Sidrane

ChangeLog

@@ -5896,4 +5896,8 @@
 	  Mikrow STM32F4 board from Ken Pettit (2013-10-27).
 	* arch/arm/src/stm32/stm32_spi.c:  DMA-related fixe from Ken
 	  Pettit (2013-10-27).
+	* sched/sched_releasetcb.c: Fix a cornercase:  If sched_releasetcb()
+	  is called as part of a failed pthread startup before the flags
+	  field in the TCB has been initialized, then a crash occurs.
+	  Pointed out by David Sidrane (2013-10-27)
 

sched/sched_releasetcb.c

@@ -168,7 +168,7 @@ int sched_releasetcb(FAR struct tcb_s *tcb, uint8_t ttype)
        */
 
 #ifndef CONFIG_DISABLE_PTHREAD
-      if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
+      if (ttype != TCB_FLAG_TTYPE_PTHREAD)
 #endif
         {
           FAR struct task_tcb_s *ttcb = (FAR struct task_tcb_s *)tcb;