stream_filter: smooth: non live streams can control pace

Fixes most of glitches for non live streams, especially on
quality change.

modules/stream_filter/smooth/smooth.c

@@ -774,9 +774,11 @@ static int Control( stream_t *s, int i_query, va_list args )
             break;
         case STREAM_CAN_FASTSEEK:
         case STREAM_CAN_PAUSE: /* TODO */
-        case STREAM_CAN_CONTROL_PACE:
             *(va_arg( args, bool * )) = false;
             break;
+        case STREAM_CAN_CONTROL_PACE:
+            *(va_arg( args, bool * )) = !p_sys->b_live;
+            break;
         case STREAM_GET_POSITION:
             *(va_arg( args, uint64_t * )) = p_sys->playback.boffset;
             break;