In r354148 the goal was to check THREAD_CAN_SLEEP() only once for the

purpose of epoch_trace() and for calling subsequent panic, but to keep
code fully under INVARIANTS, so don't use bare function call to panic().
However, at the last stage of review a true value slipped in, while
always false was assumed.  I checked that in email archive with kib@.

Noticed by:	trasz

sys/kern/subr_sleepqueue.c

@@ -325,7 +325,7 @@ sleepq_add(const void *wchan, struct lock_object *lock, const char *wmesg,
 #ifdef EPOCH_TRACE
 		epoch_trace_list(curthread);
 #endif
-		KASSERT(1,
+		KASSERT(0,
 		    ("%s: td %p to sleep on wchan %p with sleeping prohibited",
 		    __func__, td, wchan));
 	}

sys/kern/subr_trap.c

@@ -187,7 +187,7 @@ userret(struct thread *td, struct trapframe *frame)
 #ifdef EPOCH_TRACE
 		epoch_trace_list(curthread);
 #endif
-		KASSERT(1, ("userret: Returning with sleep disabled"));
+		KASSERT(0, ("userret: Returning with sleep disabled"));
 	}
 	KASSERT(td->td_pinned == 0 || (td->td_pflags & TDP_CALLCHAIN) != 0,
 	    ("userret: Returning with with pinned thread"));