crypto: avoid double free

Coverity scan reported a free after use and I think its
right. Tweak to avoid double free.

Signed-off-by: Michael Dawson <mdawson@devrus.com>

PR-URL: #40380
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>

Author: mhdawson

src/crypto/crypto_util.h

@@ -550,9 +550,12 @@ struct EnginePointer {
 
   inline void reset(ENGINE* engine_ = nullptr, bool finish_on_exit_ = false) {
     if (engine != nullptr) {
-      if (finish_on_exit)
-        ENGINE_finish(engine);
-      ENGINE_free(engine);
+      if (finish_on_exit) {
+        // This also does the equivalent of ENGINE_free.
+        CHECK_EQ(ENGINE_finish(engine), 1);
+      } else {
+        CHECK_EQ(ENGINE_free(engine), 1);
+      }
     }
     engine = engine_;
     finish_on_exit = finish_on_exit_;