lib/event_group: propagate heap_free result

sdk/lib/event_group/event_group.cc

diff --git a/sdk/lib/event_group/event_group.cc b/sdk/lib/event_group/event_group.cc
index 04d0337..446c8eb 100644
--- a/sdk/lib/event_group/event_group.cc
+++ b/sdk/lib/event_group/event_group.cc
@@ -191,8 +191,7 @@
 		waiter.bitsSeen   = bits;
 		waiter.bitsSeen.notify_one();
 	}
-	heap_free(heapCapability, group);
-	return 0;
+	return heap_free(heapCapability, group);
 }
 
 int eventgroup_destroy(SObjStruct *heapCapability, EventGroup *group)