app-layer: fix AppLayerParserProtocolIsTxEventAware

AppLayerParserProtocolIsTxEventAware would check if a proto is tx
event aware by checking if it had registered a StateHasEvents function.
However, this is an optimization function. This patch changes it to
use the StateGetEvents function instead, which is a better indicator.

src/app-layer-parser.c

@@ -931,7 +931,7 @@ int AppLayerParserProtocolIsTxEventAware(uint8_t ipproto, AppProto alproto)
 {
     SCEnter();
     int ipproto_map = FlowGetProtoMapping(ipproto);
-    int r = (alp_ctx.ctxs[ipproto_map][alproto].StateHasEvents == NULL) ? 0 : 1;
+    int r = (alp_ctx.ctxs[ipproto_map][alproto].StateGetEvents == NULL) ? 0 : 1;
     SCReturnInt(r);
 }