Fix valgrind error in tls unittest.

src/detect-tls-version.c

@@ -660,14 +660,13 @@ static int DetectTlsVersionTestDetect03(void) {
 
     result = 1;
 end:
-    if (de_ctx) {
+    if (de_ctx != NULL) {
         SigGroupCleanup(de_ctx);
         SigCleanSignatures(de_ctx);
+        DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx);
         DetectEngineCtxFree(de_ctx);
     }
 
-    DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx);
-
     FlowL7DataPtrFree(&f);
     StreamTcpFreeConfig(TRUE);
     FLOW_DESTROY(&f);