rule reload: fix unitialized memory access on error

Coverity 709220

src/detect-engine.c

@@ -499,6 +499,9 @@ static void *DetectEngineLiveRuleSwap(void *arg)
     DetectEngineThreadCtx *old_det_ctx[no_of_detect_tvs];
     DetectEngineThreadCtx *new_det_ctx[no_of_detect_tvs];
     ThreadVars *detect_tvs[no_of_detect_tvs];
+    memset(old_det_ctx, 0x00, (no_of_detect_tvs * sizeof(DetectEngineThreadCtx)));
+    memset(new_det_ctx, 0x00, (no_of_detect_tvs * sizeof(DetectEngineThreadCtx)));
+    memset(detect_tvs, 0x00, (no_of_detect_tvs * sizeof(ThreadVars)));
 
     SCMutexUnlock(&tv_root_lock);